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The bloke doing the flow testing should have some insight into exactly what's happened there. You should be able to hear a difference in the air flowing when flow drops that much and sharply so. Could it be a problem with his bench?

Always the simple things that you never expect to fuck up And it was my silly question not bears

Yeah good point sly but under the washer bottle would have good airflow (from the gap down the side of the radiator). I've never touched it after driving but I'll try and remember next time

I did mine that way simply so I could use the supplied wiring without needing any more joins. The only extra I needed was battery 12v + & - The instructions recommend that you mount it in a well-vented spot. I read up a lot about this very issue and found that glovebox mounting wasnt necessary and not recommended by the manufacturer due to cooling issues. But each to their own really, whatever works. My take is that they made it with a finned alloy case for a reason: to shed heat.

Have to be careful about signal noise from other wires near the trigger circuit. The coil wires need to be separate from them too, otherwise it may self-trigger. Keep runs as short as you can. I run mine under the washer bottle and a bit forward of it, away from passenger side exhaust (clevo). I've hit deep puddles and it's never missed a beat. They're supposed to be reasonably water-resistant (off-road racers use them a lot).

Do they make crank scrapers for clevos? I know windsors are no problem to get

Theoretically yeah but in practice would introduce other problems like reduced suspension travel, (with more leverage comes less movement), spring clearance on the bump stop plate, spring angle on the top of the tower, plus where to put it on the arm itself. With all these potental issues and the amount you can actually move it may make the whole job not worth the trouble for the gains it might give.

Ok silly question but is your choke working ok?

If you could describe said difficulty when cranking that would be very helpful. Does it crank slowly? (starter or battery) Does it start cranking slowly but then hit its stride after a few seconds? (one pole out in the windings) Does it fluctuate fast-slow-fast (like the timing is too advanced) Does it just crank at normal speed but for long periods before firing? (spark issues) You can still have an old oil-filled cannister type coil but it can be 12v. You have to look on it to see if it's 9v or 12. If it's 9 it should have a sticker telling you to use a ballast with it.

I'll add that if it's a factory coil suited to points it will be a 9v ballast type with a resistor or the supply wire itself is a resistor wire. If you have a later electronic coil you'll need to run a 12v supply to it, otherwise it will put out a shitty spark

Yes this is a major built-in characteristic of 70s-era cars, famously demonstrated in the HQ Holden. The American engineers (who dictated GM policy to the Aussies) insisted that all passenger cars have understeer to make the passengers feel safer, at the expense of driver enjoyment. They turned what should have been a superior-handling car (with coil spring rear!) to the Falcon, and turned it into a sloppy mess of a yank barge, but scaled down. Fords were better, but still not great. A lot of those cars that have built-in understeer achieve it with positive camber gain under compression (ie tipping the wheel out under load). This is the opposite to what you want for best roadholding. Moving the top arm pivot point creates, like sparky Dave said, a virtual pivot point in the geometry where if you draw an imaginary line through the top and bottom arms, they intersect somewhere around the opposite wheel or a little outside. Stock geometry has them never intersecting at all.

One trick I sort of remember with the radius rod donuts is to compromise and do one side of the rod in urethane and the other in rubber. I can't remember exactly which goes where but I'd assume the softer one goes on the front (outside) and harder on the rear (inside) to reduce deflection when the arm loads up on turns, but still has some compliance. The softer bush on the front can compress as the arm is forced backwards when hitting a bump.

Konis for the win.... A long-term investment as they are rebuildable and to any spec you like. My 2c on the "Shelby drop"..... If the spring perch is roughly halfway along the arm, and the ball joint is the fixed end (connected to the ground) then moving the pivot point for the arm bush downward 1" would move the spring perch down roughly 1/2", lowering the car by this amount. Not a bad result for the price of a drillbit, and Shelby definitely had a clue about doing stuff to cars. Has the added bonus of increased camber change throughout travel.

Leaf-sprung rears don't have lateral location, that's the whole point of them.... Simplicity. Although some have additional radius arms to prevent axle tramp. Late Falcon Utes have them. Nothing stopping you from installing a watts-link diff hat onto a leaf housing and fabricating body mounts for the links. Will need engineering though.

They are a small bore, long stroke (90.2 x 105.8), undersquare much like a 250 crossy but even more so. That's over 4" of stroke, more than a 400. So whatever rpm constraints a crossy might have, these Barra 220s would be similar. I'd think a good limit to work with would be 6250, up from factory 5500 (I think). The highest rpm on a factory 5.4 was the Boss 315 at 6500. They'd have some quality bits in them I'd imagine.

Not arguing what is better at all, I know QuickFuel is more jazzed-up and appears to be better value than Holley, if not made in USA. I like the removable air bleeds a lot. Secondary tuning seems smarter on both mech and vac models. Mech secondaries can be opened at 30%, 60% or 1:1 with primary with a simple linkage change. Vac sec tuning looks good too with a simple turn of a needle screw in or out (no swapping springs). This whole discussion started on Holley model numbers which bear no resemblance to QuickFuel models.

DOHC = big valve area, low velocity SOHC = small.valve area, high velocity. Although those engines still have 2 inlets like a DOHC so that theory really shouldn't apply. More likely the tune of the engine than anything. Problem with the Boss motors was that by the time the heads started breathing properly, the long-stroke bottom end became the mechanical limit.

600 vac is the right choice for a warm 5-litre V8. I ended up going with a spread-bore 650 with annulars in the end, to try and get some economy out of it. My original 600 now sits on the shelf.

Might need good rods.... Long-stroke engine designed originally for a truck means rpm wasn't a priority. Chip and exhaust could easily bring these up to Boss 260 spec, with better bottom end torque. Valve springs are a bit poo from stock. Plenty of go-fast bits available from trick-flow, etc. Fitting to an early falc probably needs strut conversion and tower notching kit. These are very wide engines like the DOHC versions.

Probably for a truck application

Yeah but we're talking actual Holleys not aftermarket ones like QuickFuel or BG, in which case anything goes.

60/12v = 5A X 2 lights = 10A + (2 x leds @ 3.75A) = 17.5A total for that circuit. That 60W rating is equivalent light output. Actual consumption would be 3.75 x 12 = 45W. Not real efficient for LEDs but a lot of that power goes into the electronics.

4150 is the classic 4-barrel Holley, designed for performance aftermarket applications. 4160 is the same basic design but is more emissions/factory oriented, and will be calibrated as such. As already stated the 4160 has no secondary block which means no power valve, emulsion wells, acc pump passage or replaceable jets. Instead they have a simple plate with the main jet sizes drilled into it along with a primitive emulsion tube and idle feed. A 4150 can be DP or vac, but a 4160 is always vac only. The metering plate doesn't allow the acc pump tube to connect to the carby body, thus making all 4160s vac bodies. Either can be Ally body or die cast Zinc, (which is miles better, trust me). Heat soak is a biggerbproblem on ally carbs. My 4160 is a 600 and has a Zinc body, single fuel inlet and fixed side-hung floats. It lists as a factory Ford replacement on an F-series truck and even has a Ford part number stamped next to the Holley list number. It has an emissions type reverse idle screw. The 4160 can be converted to a 4150 simply by installing a meter block on the secondary side and longer fuel transfer tube (if it's a single fuel feed). In anything but a race car, this isn't needed. The beauty of the meter plate is that it eliminates the power valve and idle screws out of the equation, making the secondary side a set-and-forget item. Likewise, on a 4160 the fixed float bowls can be swapped for adjustables and can be converted to dual feed bowls if needed (say for an alcohol carby). By the time you did all that, you could just have bought the carby you wanted, but it demonstrates how brilliant the modular design is, that you could mix and match so many different parts to get the combo you need. You really do need to be scientific about it though. Just keep this in mind: DP for race Vac for street Each is calibrated for its intended purpose and when one is used for the opposite role, it needs to be heavily reworked to suit.

That cam's definitely not fucking around. Hope your valve gear is as serious at that lift.

Definitely no excuse for the heads to be holding it back now. 20 cfm should be worth 30-40hp. Can't believe the valves were a single cut to start with. Seats as well?