Trent250

The 2 pics below are the reason I don't think the above stainless is suitable for exhaust. Also keep in mind that when metal is at different temperatures it expands and contracts at different rates, so the black areas on the exhaust below are much much cooler than the coloured sections. When metal expands and contracts at different rates it cracks, more so in harder steels
 

 
 
From what I have learned/been shown (by blacksmiths with over 40 years working experience) the temps are a little off on the below chart but give a pretty good indication of temps when metal turns to a certain colour
 

WOW 42mm ID and 50mm OD means 4mm wall, that's A LOT bonus is they should resist cracking a bit more.
The marks on the bottom are interesting as they start just after the bend but extend all the way along the pipe to near the flange, and even though the flange looks like its had a touch or 2 you would think that if the pipe has hit then flange would be smashed but it isn't. On my extractors I had a hell of a time trying to seal the pipes where they are really close as you just can't get in there to weld. I would be looking at cutting in the straight section before the last bend and putting in angled pieces to lift the rear section up a bit. This CAN'T be done without the extractors being on the car to make sure it passes the gearbox crossmember fine.
If you changed the transition between where the secondaries meet and the flange to join to the exhaust it would help a fair bit with performance, if you have a look around the internet at collectors and transitions you will get the idea. Will it make a difference yes but running what you have now will be fine until you want better.

50mm primaries? Really? That's big unless they are really thick. Secondaries are about right, primaries should be 42-44mm.

Nice long primaries, are 6-2-1 so scavenging isn't going to be the best, merges look smooth but cant tell for sure from outside. Look well made from what I can see. All mandrel bends and they've tried to keep them all the same length. Might be tight fit in the bay.

They look good. will they work I don't know, but hey they look good

Hi guys, I picked up a set of extractors and wondering what u think of them? Any good? There stainless steel and 3" outlet..

I should probably cut them some slack.  Maybe it occurred from the factory.  The engine I pulled the STD STD crank from had March 1983 Ford bearings in it so I think it has never been apart.  Funny thing is the bottom side of the thrust bearing was not fitted with a proper thrust bearing - just a normal shell.  Very weird.  Perhaps this engine is just another factory oops???
 
No really the local shops are not much chop on anything other than stock stuff.  It is pretty scary because in a few short months we will have a drag strip 50 minutes away and a lot of rich business people are buying race cars from down south.  Imagine what is going to happen when they need machining....
 
I will continue to send all my stuff south as I am sick of being lied to by the local shops.  Like saying they balanced the engine and two of them came back without a mark on them.  second one was a customer engine so I sent it south to Cam @ Engine Engineering and surprise surprise, it had not been touched. 
 
I refused to pay the bill for the local machining and they threatened to take me to court.  No worries I said, I'll see you there with the reports from an independent machine shop that proves you never did the job you want to charge me for.  Still waiting for the summons.  That was two years ago. 

Trent 250 - time to start listening to the people on this forum that actually know what they are talking about like Rob and dare I say me.
 
READ the thread "need help, missing high performance crossflow".  The author of that thread is no newbie wantabe and has been racing for a damn long time.  I spoke with him personally so I know his credentials.  He tried everything to make the XE style dizzy work - as most people - including me, have done.  Put simply - THEY ARE USELESS IN ANYTHING BUT A STANDARD APPLICATION.
 
He went to TFI and guess what - problem solved.  Notice how he is no longer contributing to the thread - That is because he fixed the issue.  He is not a big forum person and only joined as he had tried everything to make the XE style dizzy work and in desperation he turned to this very forum and LISTENED and TOOK the advice of those in the know and look - No more problems.
 
I know its hard knowing who to trust sometimes BUT mate you need to TRUST the people on here.  We are here to help and we HAVE some of the toughest x-flow in the country under our belts. 
 
 
 
 

Annnnnnnnd a DP but only if it has over 10.5 comp and over 250 @ 50 duration camshaft...other wise you have to run em too rich to get decent response out of em and you kill plugs and wash the bores in fuel.
 
Just saying

Thanks for the pics mate, I see the difference now...
Just messaged Aussie speed and it fits a square bore..
Cheers

Never owned one but i believe aussie speeds are square bore. Generally, when something is described as "4-barrel" it's automatically assumed that they're referring to a square bore carby.
 
"Square bore" = all barrels same (or close) in diameter and are on hole centres that when viewed from below, represent a square.
 

 
"Spread bore" = 2 small primaries and 2 big secondaries. The centres for the primaries are further apart than the secondaries, so as to form a "spread" shape when viewed from below.
 

 
Both are universal patterns (ie manufacturers all stick to the standard for either) but neither type is directly interchangeable for the other without an adaptor. The bolt patterns are different too.
 
Best way to confirm the manifold is to ring aussie speed.

No harder or easier than a mechanical one, it's 4 bolts, throttle linkage, fuel hose(s), choke wire or cable. The vacuum setup is all part of the carby and comes with it.

Going mechanical secondaries
... got a mate that works at a petrol station huh?
 
Is there a particular reason why you need one of them? Just wouldn't want you to get it and be bitterly disappointed trying to get it right without pouring fuel down it.
 
Holley makes vac and mech carbies very different from each other for a good reason. Mech is for racing, vac is for street. The assumption with mechanical carbies is that you wont be cruising or idling much. Their emphasis is on absolute performance, and run big jets accordingly. Now here's the clincher.... You go and jet down because it's a fat pig and guess what? It falls on its face (goes lean) It's because they run small power valve channel restrictors, along with big jets. You can drill the PVCRs out and jet down but that's even more work. A mechanical carby can be made to work on the street on a (relatively) small engine like many have on here but there's the thing... Why not just get the right one?
 
Vac sec carbies are jetted pretty well out of the box for cruising and have a bigger enrichment circuit (PVCR) for when you stomp it. Also the secondaries (if set up right) only open if (and as far as) they need to.
 
Again, not knocking your suggestion if you know it will be what you want but you just want to be 100% on what to expect from a race carby vs a street one.

I just brought the scorpion roller rockers, msd 6al2 programable and coil to suit..
Next is a 600 mechanical holley..
Where can I get one from, they seem a bit hard to find as most are vac secondaries..
Thanks

Just did, take a look...

Someone will confirm but you will need rockers to suit cleveland not windsor. Yes 5/16 is what you want if you want bolt on. Yes 7/16 will require extra money spent on getting the head machined to suit larger stud size.
The link to the scorpion rockers I provided if a 6 cylinder engine so you only get as many as you need not the extras for a v8. Search this site for scorpion rockers as I posted an email that was sent to me by scorpion regarding fitment. If you buy the 6 cylinder scorpion from summit racing it should be on your door step for less than $300 aussie dollars. Then again you could find a set of used yella terra for the about the same price or pay double for a new set.

Blar blar blar blar... hooked him
 
Just because 7500RPM xflows sound soooooooooooo good 
 

 
P.S and with locked timing LOL

Start a build thread with pics of the car Trent and ideas and what you want...people can help better when there's a car to look @ on some things you don't notice.

Once again
wagoon= simplistic dribble that compares apples to oranges using bananas as an example
 
then
 
Someone who knows what they are talking about= someone who knows what they are talking about and makes sense with a technical bases to the argument

The Streetfire does not have the ability to alter the signal received from the distributor. So whatever you set at the crank is what you have - from idle to whatever your rev limit is.  Very popular in 80's drag racing scene because the engine is tuned to perform over a very narrow (2000 rpm) band.
 
The 6AL2 PROGRAMMABLE has the ability to take the signal from the distributor and give you an advance curve, just like your engine had when it left the factory.  In reality the 6AL2 takes the signal from the distributor and retards it (via the run retard Graph - advance curve, backward if you like) to give the engine what timing it needs throughout the rev range is 100 rpm increments.
 
TO make it SUPER SIMPLE - THE WORST IMPROVEMENT I HAVE SEEN ONE OF THESE 6AL2 PROGRAMMABLE IGNITIONS MAKE IS 15RWHP.  With a moderate curve I improved this another 15 RWHP.  That is 30 RWHP gain when compared to LOCKED TIMING.
 
I can not EMPHASISE how good these things are - BUT at the end of the day - DO what YOU want.  I can only advise on what I and MANY others have found with using the 6AL2 on a crossflow. 

Good work Sly. Couldn't have written it better.
 
Agree that a smaller carb could be used for a more commuter friendly engine. Will loose out above 5-5,200rpm, but how often do you use revs above that? But then again a smaller cam will make it more friendly as well.
 
If you have a big cam the carb might as well match in my opinion.
 
Good thread!

I know all the folks in the know swear by carbies around the 600 mark, but here's an article where they test a whole bunch of Holleys on a stout 383 SB Chev, and the results are very interesting.
 
http://www.superchevy.com/how-to/148-0403-seven-holley-carbs-test/390-cfm.html
 
The smallest one they chucked on, (the 390) despite obviously choking an engine that size, still made 409 hp and got good torque all the way up to it.
 
So if you plan on making anywhere near that power (and i doubt you will) maybe a smaller carby like a 390 or 465 is a smarter choice.

I personally like the 465, great all round size and vac secondaries.

If using a dizzy, use a TFI. Easiest way to run it is to remove the module on the side and replace it with an EST plug or connect directly to the prongs. Very easy. A new Bosch coil is fine or get one from MSD.
 
Any good carb over 570cfm. I would use a nice choke-less 600 DP.

Should say any carb 570-650, not anything over 570 haha.