Holley 4160 too rich

[rgallucci]

I am running a Holley 4160 (650 cfm) on a '70 302 in a '67 convertible.

Specs:
stock 351W heads
Comp Cam roller tip rockers
Sig Erson cam: .447 lift, 222 degree duration
stock exhaust manifolds (headers as soon as I can afford them)
Aftermarket dual exhaust, with H-pipe, and Flow Masters
Weiand Stealth intake
Mallory Unilite conversion electronic ignition of stock distributor

My problem is that I am getting a too rich condition when stomping on the gas--lots of black smoke. Obviously it is an acceleratory pump problem, but the carb only has a 30 cc pump, with .025 accelerator pump nozzles (the smallest available). I am thinking of playing with the pump cams, currently using a yellow cam, but not sure if this will help.

Any Holley guru's out there with suggestions?

Thanks.

 

[Max Power]

Maybe the wrong or defective power valve? Have you had it on a dyno to check richness at all throttle positions and rpms? What jets are you running?

That's a little too much carb for stock manifolds and that cam, but I think you can make it work. I would start with a fresh rebuild and tune from there.

 

[rgallucci]

Thanks for the reply.

I recently rebuilt the carb, and replaced the original size 67 jets with size 64 jets since it was idling too rich. That seemed to do the trick. I didn't notice what size the new powervalve was.

I also missread the duration of may cam, it is 222° at .050", and 284° advertised duration. Oops.

I haven't had the chance to put it on a dyno, I really haven't gotten that far yet.