Poor low end response...

[DocDirk]

Hi! This is the end of my second year of working on my build, a West Coast. I've read about every thread I can find on this awesome forum about HP/Torque/Intake manifolds, exhaust impact on performance, dyno vs chassis dyno, rear end gear preferences, cam choices, etc. but as an amateur cobra builder I'm still stumped. I've a 533BB in my West Coast, built by Ford Performance Solutions in Anaheim. Intake is Victor Jr. with a Demon 850 annular single carburetor. Engine dyno'd about 650 HP at 5200 and about 500 torque around 3500 maxxing about 640 (where is that sheet..??). I don't have the cam specs right now. Transmission is a built up C6 (by the same shop) and I believe the ratios are 2.46, 1.40 and 1.00. It has a Ford 9" rear with a 2.75 gearset (recommended as optimal by the kit mfgr). Tires are 295/50/15 rear and 265/60/15 up front. I set the timing at 15 degrees, with 32 degrees total advance. Kitcarbp suggested I really won't know how it can behave until I've had it tuned on a chassis dyno.

I've only driven it a few times so far but under 3500 RPM the engine feels "like pushing a rope". I've considered changing over to the Performer RPM intake manifold (the kit manufacturer recommends the Torquer II for hood clearance), but my engine builder doesn't think that will help as much as I think, while costing me a lot at the top end. I'm planning on changing my rear diff from an open one to a posi, so the rear ratio might be raised in the process (3.08? 3.25?) I'm planning to drive mostly street and cruising on trips, so I'd hate to push the gearing to the point of having to run 3K RPM on the freeway. There doesn't appear to be room for a GearOver between the transmission and the rearend, and they're pretty expensive. Restrictive use of my ankles after many surgeries leaves me unable to confidently use a manual transmission. The exhaust is collects into 3 1/2" pipes with inner baffles the mfgr supplied, long with fibreglass wrapping outside of a 2" inner diameter. Have I built a car that's only any good at high RPM's? I haven't weighed this car but with the beefier chassis and added length and width (6" and 4") it'll surely be heavier than most other cobras.

Well with all the uncertainty brought on by my inexperience I wonder what any of you might do to make this car more fun to drive - it just doesn't seem to "launch" at all, doesn't have the kick in the pants I was expecting from the setup. As usual my enthusiasm has exceeded my wisdom and experience by quite a long shot.... Any suggestions / feedback would be appreciated!

Dirk