XFChris

Well the engine that came with my new shop ute has a munched cam bearing (number 2) so it is time to finally put together the 'Mad scientist' crossflow.  This engine will be pieced together from left over crossflow bits from my speedway career and general hunting and gathering.
 
Here is quick run down;
 
Yella Terra street terra bolt on adjustables on a D head with moderate porting and a multi angle seat cut.  Not really sure on the head flow figures but the engine it was on made 270rwhp on fuel so good enough.
 
Bottom end will be a 78DA block, .030 that I picked up locally for $20.  It is honed and fitted with new cam bearings and the crank is unbalanced.  Slugs will be ACL 8.5cc (now 10cc thanks to inlet reliefs) 200 rod pistons on balanced 200 rods with ARP rods bolts.
 
Camshaft is a very old CROW 619 Hydraulic.  Not ideal but it is what I have and I want to finally use it.  I have a new set of Clevite anti pump up lifters so they will go in with a one season old Rollmaster Double Row Timing chain.  Pushrods will be a set of tapered XC factory units (they are strong little buggers).
 
The Shop ute cam with off the shelf Lukey extractors and I have fitted a press bent 2.5" exhaust with a singe muffler (no resonator) that I had lying around. Compression should end up at 10.3:1 and I will be running an Aussiespeed 2 barrel manifold with a Keith Dorton 350 Holley initially.
 
The plan is to build and run the engine like this and once it is 'run in', I will dyno it and see what we end up with.  Then I will change to a reco 500 Holley and see what happens on the dyno. 
 
I have a dirty old CAIN four barrel manifold here and a 600DP so that will also make it's way on in the future and if I can con a new Aussiespeed 4 barrel out of Mark I will test them back to back to show how superior the Aussiespeed unit is. 
 
Whole object of this engine is to show people what can be achieved with careful parts hunting and scavenging.  It wont be an all time horsepower king, but it will be fun.  I will update this thread with results so stay tuned.

The guy that is selling it has it on FB Speedway parts or something.  If you are serious I have his contact number as he is a customer.  I know that he is going up the dam for Easter so he will not be selling it over the break.
 
PM me after the Easter break and I'll hook you up.
 
Honestly all the talk of 200 rods for this engine is overkill.  Leave that for the drag and speedway guys.  For the street you want low down grunt and torque and the 250 rods create that it bucket loads. 
 
Gavin Fletcher's all conquering Q1 XF modified production hardly ever revs over 6000 rpm and is stupid fast.  Why - because of the torque.
 
use the strength of the these motors - get a good flowing head with a decent size stick - good induction - good exhaust and good spark and you cannot go wrong.
 
After Easter I will get the Mad Scientist X flow together.  It will make stupid grunt and decent HP and has been made out of left over stuff. 
 
That is the beauty of these engines.  There a plenty of good second hand parts that can be purchased cheaply and if you know what you are looking for and a careful in what you buy - you can make serious power for bugger all.
 
Buy everything new and change plans and paths and you will spend stupid money and probably go no better that the budget route. 

Used them a couple years back on a commodore. Gripped great when new, very tall tread so they were decent in the wet. Until 6 or so months later, a bit of wear and tear made them much less grippy.
 
Not sure if I would use them on the roads these days, I actually care about the cars I drive now.

RIDE AND ROLL RESISTANCE-SPRING

Too much spring: overall
• Harsh and choppy ride
• Much unprovoked sliding
• Car will not put power down on corner exit – excessive wheel-spin

Relatively too much spring: front
• Understeer – although the car may initially point in well
• Front breaks loose over bumps in corners
• Front tyres lock while braking over bumps

Relatively too much spring: rear
• Oversteer immediately on application of power
• Excessive wheel-spin

Too little spring: overall
• Car contacts the track a lot
• Floating ride with excess vertical chassis movement, pitch and roll
• Sloppy and inconsistent response
• Car slow to take a set – may take more than one

Relatively too little spring: rear
• Excessive squat on acceleration accompanied by excessive rear negative camber, leading to oversteer and poor power down characteristics
• Tendency to fall over on outside rear tyre and ‘flop’ into oversteer and wheel-spin

ANTI-ROLL BARS

Too much anti-roll bar: overall
• Car will be very sudden in response and will have little feel
• Car will tend to slide or skate rather than taking a set – especially in slow and medium speed corners
• Car may dart over one wheel or diagonal bumps

Relatively too much anti-roll bar: front
• Corner entry understeer which usually becomes progressively worse as the driver tries to tighten the corner radius.

Relatively too much anti-roll bar: rear
• If the imbalance is extreme can cause corner entry oversteer
• Corner exit oversteer. Car won’t put down power but goes directly to oversteer due to inside wheel-spin
• Excessive sliding on corner exit
• Car has a violent reaction to major bumps and may be upset by ‘FIA’ kerbs

Too little anti-roll bar: overall
• Car is lazy in response, generally sloppy
• Car is reluctant to change direction in chicane and esses

Relatively too little anti-roll bar: front
• Car ‘falls over’ onto outside tyre on corner entry and then washes out into understeer
• Car is lazy in direction changes

Relatively too little anti-roll: rear
• My own opinion is that on most road courses a rear anti-roll bar is a bad thing. Anti-roll bars transfer lateral load from the unladen tyre to the laden tyre – exactly what we don’t want at the rear. I would much rather use enough spring to support the rear of the car. The exception comes when there are ‘washboard ripples’ at corner exits, as on street circuits and poorly paved road circuits.

SHOCK ABSORBER FORCES

Too much shock: overall
• A very sudden car with harsh ride qualities, much sliding and wheel patter
• Car will not absorb road surface irregularities but crashes over them

Too much rebound force
• Wheels do not return quickly to road surface after displacement. Inside wheel in a corner may be pulled off the road by the damper while still loaded
• Car may ‘jack down’ over bumps or in long corners causing a loss of tyre compliance. Car does not power down well at exit of corners when road surface is not extremely smooth

Too much bump force: general
• Harsh reaction to road surface irregularities.
• Car slides rather than sticking
• Car doesn’t put power down well - driving wheels hop.

Too much low piston speed bump force
• Car’s reaction to steering input too sudden
• Car’s reaction to lateral and longitudinal load transfer too harsh

Too much high piston speed bump force
• Car’s reaction to minor road surface irregularities too harsh – tyres hop over ‘chatter bumps’ and ripples in braking areas and corner exits.

Too little shock: overall
• Car floats a lot (the Cadillac ride syndrome) and oscillates after bumps
• Car dives and squats a lot
• Car rolls quickly in response to lateral acceleration and may tend to ‘fall over’ onto the outside front tyre during corner entry and outside rear tyre on corner exit.
• Car is generally sloppy and unresponsive

Too little rebound force: overall
• Car floats – oscillates after bumps (the Cadillac ride syndrome)

Too little bump force: overall
• Initial turn in reaction soft and sloppy
• Excessive and quick roll, dive and squat

Too little low piston speed bump force
• Car is generally imprecise and sloppy in response to lateral (and, to a lesser extent longitudinal) accelerations and to driver steering inputs

Too little high piston speed bump force
• Suspension may bottom over the largest bumps on the track resulting in momentary loss of tyre contact and excessive instantaneous loads on suspension and chassis

Dead shock on one corner
• A dead shock is surprisingly difficult for a driver to identify and/or isolate
• At the rear, that car will ‘fall over’ onto the outside tyre and oversteer in one direction only
• At the front, the car will ‘fall over’ onto the outside tyre on corner entry and then understeer.

WHEEL ALIGNMENT

Front toe-in: too much
• Car darts over bumps, under heavy braking and during corner entry – is generally unstable
• Car won’t point into corners, or if extreme. May point in very quickly and then dart and wash out

Front toe-out: too much
• Car wanders under heavy braking and may be somewhat unstable in a straight line, especially in response to single wheel or diagonal bumps and/or wind gusts
• Car may point into corners and then refuse to take a set
• If extreme will cause understeer tyre drag in long corners

Rear toe-in: too little
• Power on oversteer during corner exit

Rear toe-in: too much
• Rear feels light and unstable during corner entry. Car slides through corners rather than rolling freely

Rear toe-our: any
• Power oversteer during corner exit and (maybe) in a straight line
• Straight line instability

Front wheel caster or trail: too little
• Car too sensitive (twitchy?)
• Too little steering feel and feedback

Front wheel caster or trail: too much
• Excessive physical steering effort accompanied by too much self return action and transmittal of road shocks to the drivers hands
• General lack of sensitivity to steering input due to excessive force required

Front wheel caster or trail: uneven
• Steering effort is harder in one direction than in the other
• Car will ‘pull’ towards the side with less caster – good on ovals, bad on road courses

Camber: too much negative
• Inside of tyre excessively hot and/or wearing too rapidly. At the front this will show up as reduced braking capability and at the rear as reduced acceleration capability. Depending on the racetrack and the characteristics of the individual tyre, inside temperature should be 10°-25° hotter than the outside. Use a real pyrometer with a needle rather than an infra red surface temperature device.

Camber: not enough negative
• Outside of tyre will be hot and wearing. This should never be and is almost always caused by running static positive camber at the rear in an effort to avoid the generation of excessive negative camber under the influence of aero download at high speed.
• A better solution is improved geometry and increased spring rate. Dynamic positive camber will always degrade rear tyre performance and if extreme, can cause braking instability and/or corner exit oversteer.

Bump steer, front: too much toe-in in bump
• Car darts over bumps and understeers on corner entry

Bump steer, front: too much toe-out in bump
• Car wanders under brakes and may dart over one wheel or diagonal bumps
• Car may understeer after initial turn in

Bump steer, rear: too much toe-in in bump (same as solid axle steer on outside wheel)
• Roll understeer on corner entry
• Mid phase corner understeer
• ‘Tiptoe’ instability when trail braking
• Darting on power application on corner exit

Bump steer, rear: too much toe-out in bump (same as solid axle steer on outside wheel)
• Instability on acceleration
• Good turn in followed by a tendency to oversteer at mid-phase and exit

TYRES

Too much tyre pressure
• Harsh ride, excessive wheel patter, sliding and wheel-spin
• High temperature reading and wear at the centre of the tyre

Too little tyre pressure
• Soft and mushy response
• Reduced footprint area and reduced traction
• High temperatures with a dip in the centre of the tread

Front tyres ‘going off’
• Gradually increasing understeer – Enter corners slower, get on power earlier with less steering lock

Rear tyres ‘going off’
• Gradually increasing power on oversteer – Try to carry more speed through corner and be later and more gradual with power application

LIMITED SLIP MALADIES

Limited slip differential wearing out
• Initial symptoms are decreased power on understeer or increased power on oversteer and inside wheel spin. The car might be easier to drive, but it will be slow
• When wear becomes extreme, stability under hard acceleration from low speed will diminish and things will not be pleasant at all

Excessive cam or ramp angle on coast side plate (clutch pack) limited slip differential
• Corner entry, mid-phase and corner exit understeer. Incurable with geometry changes or rates – must change differential ramps. In 1998, virtually everyone is running 0/0 or 80/80 ramps.

SUSPENSION GEOMETRY

Excessive front scrub radius (steering offset)
• Excessive steering effort accompanied by imprecise and inconsistent ‘feel’ and feedback

Excessive roll centre lateral envelope: front or rear
• Non-linear response and feel to steering input and lateral ‘G’ (side force) generation

Rear roll centre too low (or front r/c relatively too high)
• Roll axis too far out of parallel with mass centroid axis, leading to non-linear generation of lateral load transfer and chassis roll as well as the generation of excessive front jacking force.
• Tendency will be towards understeer

Rear roll centre too high (or front r/c relatively too low)
• Opposite of above, tending towards excessive jacking at the rear and oversteer

Front track width too narrow relative to rear
• Car tends to ‘trip over its front feet’ during slow and medium speed corner entry, evidenced by lots of understeer (remember trying to turn your tricycle?)
• Crutch is to increase front ride rate and roll resistance and increase the camber curves in the direction of more negative camber in bump (usually by raising the front roll centre)
 

This mod was inspired by Stumper's thread on Street Stock Speedway and the carby mods he's done. When i had my 4011 Holley apart the other day, I noticed that the barrels had some pretty rough casting marks and misalignment between the top and bottom halves of the Venturi.

Might not show there but it's like they took the safe approach with their mouldings and made the top half slightly narrower than the bottom (so there's no chance of any ledge jutting out) with a distinct inward ridge all round. I looked at the finish and all i could see was turbulence and restriction, yet on my little 302 it probably wouldn't make any difference, or so i thought. Regardless, i just couldn't help myself...
 
Anyway about 10 min with my little Dremel and this is the result:

 
So i slapped it all back together and did notice a smoother transfer to main circuit but was a little doughy up top compared to before. I figured that more air was flowing around the booster instead of through it, so less fuel was being pulled out and needed more jet to compensate... So i thought (again). Chucked in some 70s up from 67s and it went worse!
 
Yesterday i chucked in some 64s and was slightly better, so today i thought I'd go way down to 61s and blow me down, it's going pretty good! Maybe the extra flow is giving more velocity and more booster signal, so it draws fuel harder. Hard to tell what's the go in this hot humid weather but it's fine for now.
 
What I'm trying to say is that messing with fiddly things like carbies can be trouble and can give you the opposite result to what you expect, but if you're keen to learn then this is the only way.
 
And thanks Stumper for showing what can be done with a bit of man-shed engineering

The module is just another thing that burns out on a 30 year old part that is not needed when used with a MSD that accepts Hall effects input. The module is just a sink to trim the volts back to 5volts logic and WILL fail eventually.
 
Undo the 2 screws holding the Grey motorcraft plug on and fit the EST uni in it's place to go from 6 wire out to 3 and no module. Now the only thing that can fail is the pickup but there few and far between.
 
HVC coil doe's make a difference on an banger engine for sure.   

Hi Panko.
 
Installing a security system and remote locking in your XF Ghia is not simple, it's a bit of a PITA.
 
I will help you out with the remote central locking hookup.
 
The connection will be carried out at the driver's door lock switch area, so remove the door trim and have a look around.
 
There will be lots of wires going to the power window switch and to the central locking switch and the door lock switch along with a couple to the lock actuator motor and the power window motor.
 
The system you'll need to adopt for the XF central locking is what's known as the "alternating positive door lock" system.
 
You'll need 2 x 12 volt relays, each one with all 5 pins, max rating only needs to be around 10 amps.  You'll also need some red female spade terminals, preferably unsulated ones.
 
Locate the main 12 volt feed to the door, which will be the YELLOW wire.  You'll need to tap from this to supply the 2 relays.
 
Locate the 2 wires from the door lock actuator motor that run to the switch, these will be red with yellow trace (lock) and yellow with blue trace (unlock).  You'll be cutting these wires near the place where you'll be locating the two relays.
 
You will be using NEGATIVE trigger from your alarm to each relay for both lock and unlock.
 
The relays should each be marked with terminal numbers 85, 86, 87, 87a and 30.
 
One relay will be dedicated for LOCK and the other relay for UNLOCK.
 
From the YELLOW 12 volt feed wire tap 4 wires from it with spade connectors on the ends and connect these to terminals 87 and 85 on each of the two relays.
 
Choose one relay to be the LOCK relay. Cut the red/yellow (lock) wire that runs from the actuator to the switch, fit 2 spade terminals and connect the one that goes to the switch to terminal 87a, then connect the one that goes to the actuator to terminal 30.  Connect the LOCK negative pulse trigger wire from the alarm to terminal 86.
 
The same procedure for the UNLOCK relay:    Cut the blue/yellow (unlock) wire that runs from the actuator to the switch, fit 2 spade terminals and connect the one that goes to the switch to terminal 87a, then connect the one that goes to the actuator to terminal 30.  Connect the UNLOCK negative pulse trigger wire from the alarm to terminal 86.
 
Secure the relays in a safe area away from moving parts and ensure the terminals aren't touching any metal part of the vehicle.
 
Tidy the wiring using some zip ties.
 
Installation complete.
 
If you get stuck, or have questions, PM me.

This.
I offer paint protection BUT only to those that don't give a fuck about proper maintenance. With a good coating absolutely nothing will stick to it, wax, bird shit ,nothing. If you ever need a panel restated they won't be able to match it properly because of the characteristics of ceramic/glass coatings.
Invest in a GOOD wax be it synthetic or carnauba wax. The most important part that I can't emphasise enough is a proper washing technique with the two bucket method using a grit guard ( I should start a thread on this and other polishing matters, takers?). Also a proper drying technique, if you use a chamois you should be shot. Use a proper waffle weve drying towel and a quick detailer as a drying aid.
Believe it or not but most scratches and marring happen from the owner using improper washing techniques.

Don't know if I agree with stock springs being okay in any application.  this comment can lead to the impression that you can just leave the unknown quality factory valve springs in place and away you go. 
 
These engines are getting seriously on a bit now - yes some may have been replaced along the way - but who knows unless you actually check the tension of the springs. 
 
At the very least throw a new set of 'stock' springs in it but in reality why wouldn't you just throw in a good spring like an isky 235d and set them at 95 on the seat and never ever worry about valve springs again.  This way if you decide to up the ante a bit you don't ever have to fork out for springs up to .580" lift.
 
Towing demands reliability - reliability comes from using good parts and correct tolerances.  Sure as shit is good for the garden - the one part you skimp on will be the one that bites you in the arse. 
 
I'm with you Sly - less talk - more engine building - which reminds me I have a sump to build - see ya.

Yeah they are all fair prices there, the balance is a great price.
extras that normally people have to pay that add up that you haven't had done is :  valve guide replacement, cylinder head facing on 3sides, seat inserts replaced and seats cut, refacing valves and backcut. Your block didn't get any machining except a hone in the bores so other costs are normally at least a deck face then line honing of the crank and cam tunnel, your crank only had the big ends done but not the mains, you didn't get new rod bolts done either, no head bolts there or oil pump etc etc.
All these things add up and more so if you have to have the head repaired like welding in the water galleries then refaced, have the chambers cc'd for even compression.
Don't be shocked if you have to spend $5000 on parts and machining then around $1000 for someone to PROPERLY assemble it so it lasts and can handle a flogging.
It's funny because when I port a head I charge about $600 to disassemble and inspect a head, work out the port sizes for the combination and grind the ports, before and after flow testing and then reassemble the head, this takes me at least 4 days. then the machinist charges $1000/$1500 to do the rest of the work which takes half a day, new inserts, seat cuts, facing, guides and valve grinds. LOL people think I'm making heaps out of it but I make less than a normal wage but I do it for the love and to see people go faster!!!

200 rodded 250 mate better rod angle a lot say better torque so on

You can drop straight into an 86 da block or machine the crank down or the block out if it's an 84da.
 
The longer 3.3 rods allow extra dwell at the top of stroke, ie for a given amount of piston movement you get more degrees of rotation on the crank. Hard to do seeing mahle has stopped making pistons to suit. Commodore 3.8 eco tec ones seem to be the go but then the machining costs will blow out. But I haven't done anything like that with mine.
 
A good coil is a good idea but a better one is to add a street fire cdi added onto it. It looks like doc Emmett brown with a flux capacitor belted up his ass with a hover board.
 
The injected gas can be done as the computer splices into the ford computer and reads from that and learns it's shit. Of course some of us like cooking with bbq gas, others like to run their cars on it, some like dcoe's, some like injection.
 
I like playing with injection, but the xf system is a pos. much bette when an el system runs the show.
 
And if the spelling is shit I this I apologise the auto correct is being a dumb fucking whore and I just want to shove my iPhone 6 plus up steves jobs ass. You like how that feels Steve?
 
Next they'll do a fucking 8 inch version with an app that squirts lube. Fuck!

My initial thought for this build was to use Impco 425 with B2 converter as you can fit a holley base plate to the Impco and use it on any 4 barrel manifold, but wasn't sure if a 4 barrel manifold would suit for the reason mentioned above. The 425 is really easy to use.
This next part is from research I did into running LPG on a cleveland so from all that I have learnt about crossflows it should still be relevant. Basically when picking a cam, pick a cam that has an operating range 500rpm higher than you want. The LPG lowers the working range due to the way it works differently to petrol. The ignition is crucial on LPG but you have that covered but don't forget to upgrade the coil as well.

Its 3 and 4 that get all the flow because of the proximity to the centre plenum (one that rides on top of the tapet cover) and also the throttle body. 
 
just by enlarging the ports you are not guaranteed of improving flow in and aspirated form.  anything you do to the head and runners to address the imbalance is really a band aid fix.  better to start with a better flowing manifold or make your own plenum. 
 
Thanks gerg - I know I am a crossflow freak and I'm damn proud.  Maybe I should get some stickers made up like those Vietnam vets ones (not demeaning the vets by any means - just using it as an example).

Good info gerg.  I have flow tested the aussiespeed four barrel an there is a slight difference (8cfm) on number 3 runner when compared to 1 and 2.  ten minutes with a die grinder in the right areas on 1&2 and even cfm is achieved.
 
Oh and I believe I was the one talking about even balanced manifold - not my fellow crossy freak from over in WA.  but hey all good.  The point is more important than the poster.  
 
sounds like LPG is a lot like methanol.  I know for a fact that the lpg engines I have pulled down are just a clean as a methanol engine. 

All great advice from the usual crossy freaks on here but I'll add a bit more on the LPG thing.
 
Stumper is 100% on manifold balance. My dad's XF was a warm 4.1 EFI and was a smooth revver all the way to 5500. That exact same donk in my LPG Corty with a Redline 2-barrel manifold was shitty above 4000 and felt like it was going to shake itself to bits. Bad cylinder balance from poor manifold design.
 
Now the LPG. You'll need some decent plenum volume and a manifold that will give even flow for each runner. Although EFI manifolds are more even than carby ones, they have small plenums and runners and still favour the two middle cylinders, as they are right in front of the throttle.
 
The factory rating for the EFI donk was 120 kW. Not bad for its day considering the 5.0 Dunnydoor made about that much. But the EFI manifold might only handle 150 kW before maxing out, and seeing as LPG takes up more volume in the intake than just plain air or air/petrol, that power potential becomes even less. The throttle drawing air from the hot side of the engine adds to the problem.
 
So your choice in manifolds may not be the best to reach your goal, which is to match the performance of a modern V6 (around 180 kW).
 
Ditto for the mixer. 225 is woefully small for any kind of performance engine. Go at least the next size up or a GRA single. Aussiespeed manifolds are not perfect but miles ahead of anything else, so I'd go with one of them in 4-barrel (for the plenum volume).
 
So go bigger with everything... Manifold, mixer, ports, valves, cam, exhaust... all will work together to give you what you're after. No point in having one weak link in the chain.

While where talking about this. I have a 200 rod crossy In the shed small 208 cam 10points of comp or there abouts its done 8000 km was on LPG and was built for it. went good in a auto 2.7 geared falcon I could not use it for boost so its in the corner mint engine $2500 may be another option over building one 

I have little to offer on this LPG is for BBQs but seem to work with a windmill  most of its been covered anyways

No ones ban me for trying to sell one of the engines I no longer use

Agree with Sly, Jason/TF 250 had a roller cammed crossy it is dual pattern cam and his cortina was good for 11.5.
 
I would agree with all the above, but how is your supply of LPG. Just make sure your supply of LPG is stable in quality. The better the fuel quality the higher compression you can run.
 
Not long ago I was planning a mild crossflow. Machining alone was going to be $2500 but that did include balancing. That was all new bearing, new cam and lifters, new balancer, crank grind/linish and head work. The bill will rise pretty quick if you need new pistons and a rebore, new valve spring, new valves/oversize valves which means seat size change. Funnily enough the machining work on my roller cammed crossy was only not that much more than the mild rebuild but I already had a few of the parts needed.

Ef crank if you can get one, std bottom end
 
I'd go a c2 head with efi pistons. This will give a fair whack of compression but you machine down the toungue in the chamber to reduce hot spots for pinging.
 
Standard valvegear should be ok for that too.
 
With the camtech cam it will be a torquey little bitch and pull like a serial masturbator between 1500 and 3k. I find mine is a bit meh over 3k but it has more to do with the efi manifold. I'm working on a eb manifold conversion to resolve that shortly. That should help with a boost related issue down the track.

Well Ken Moss has the fastest NAT ASP xflow and uses a dual pattern cam...I guess you can say they work.For gas I'd use a dual pattern anyway.Even if it was only for a tad more exhaust duration then inlet but same lift values.

Cheers, I'll work with the 84 DA block then
 
 
Cheers for the tips, I'll definitely take those on board. I haven't set a budget yet, I don't want to spend huge $$$, but I do want to things right the first time.
 
Ah silly me, it's the crank + pulley etc that gets balanced, might not do it if you say its not needed, though I will probably get a new crank pulley anyway.
 
 
 
Crap, meant to put CT142 503B-110a @ 208. Rev range of 1400-5000, which is one step down from the previous cam I quoted. I have heard that Crossflows do not like dual pattern cams, but it may be different when on LPG, as LPG seems to like bigger exhaust. I know a guy who can do custom grind cams so I may speak to him and see what he would recommend. Around town is where I want this car to shine. Cheers for the info.

You may find that cam a little bit big for LPG, especially an Impco 225, you might want to step back to a cam around 208 degrees, the lack of vacuum when using that cam with LPG will make the car a bit doughy off the line, I've used it before on LPG setups and found it to be a little underwhelming below 2500 rpm barely better than a stock setup.
 
The 225 will run out of puff before the cam will anyway as they only tend to run out to 4200-4400rpm.
 
Crow has a good dual pattern cam part number 14776 which is 204@50thou IN and 214@50thou EX, LSA 112 degrees, rpm range 1500-4500, while I haven't used this cam personally...Yet, I 've had more than a few blokes who run LPG tell me it works really well with the 225/EFI manifold setup as the rpm range of the cam pretty much matches the maximum flow rate of the 225, and provide excellent low down and mid range torque as well as excellent economy.
 
The Camtech cam you listed is a good cam but it is definitely better suited to petrol setups, I used it on my XC with two different type of LPG setup and it was good out on the highway and had plenty of legs which matched the impco 425 that I was using, but it was hard to live with around town and it was embarrassing having some spikey haired little punk in a corolla smash my XC off a set of lights up to 60 km/h.
 
As for comp ratio aim for 10:1 or slightly higher, that will work well with LPG.

You can go high 10's on comp with straight gas, I would use the C2 head as gas likes lots of chamber swirl to produce torque, if your going to use the EFI manifold then weld up the injector bosses so you can grind out that section to match the head, that section of manifold has a small cross sectional area so it needs to be opened right up and then matched to the runner tubes as well.
The 86 block has a 1 piece rear main the same as e series blocks, the 84 also has a 1 piece but it is a different size, I always like to run an EF crank in a 86 block as like Tony said I find them smoother.
Head work, well I'm always going to recommend some porting hahaha but with gas I would run a bigger exhaust valve, gas likes more exhaust flow. Intake if the budget allows to run a 1.84 valve then do it, a nice 3 angle seat and a backcut on the valve and your golden.
That cam will suit what your after in my opinion.
PS you don't get a block balanced you can get the rotating assembly balanced but in this application I wouldn't really worry about it.

I think the later blocks are essentially the same as the earlier blocks - possibly a bit better casting - possibly not.  won't really matter unless you plan on going .060" oversize and big comp - which you are not.  The EF crank in the 86DA block does make them RPM happier and seat of the pants feel between to two is that the EF crank is smoother.  having said that - when I bolted on a better balanced inlet manifold to my 84da block motor is RPM'd like an EF crank motor, so maybe there is something in that.
 
EF crank seal and 86da block seal are different to 84da neo seals from memory. 
 
I have little experience with LPG but I have heard that it can take a little higher compression than fuel - but to be honest I am well and truly out of my depth as I have never played with cooking gas.  I'm sure someone else on here has. 
 
the rest of the combo sounds good.  Torque will be your friend in this application so comp and cam to suit and 250/250 rod combo is the go. 

Id check the wiring for the speaker from the head unit / amp to the speaker by running a new "temporary" wire. this is the cheapest and easiest step to fault finding.
 
If you have swapped around speakers and the fault stays in the same spot then it is more likely the amp/ headunit amplifier sircuit failing.
 
I had this a couple of times with a Pioneer amplifier i paid a shit load for years ago. Solder joints internally were lousy and caused a lot of issues including crackling and popping.