I am having a tuning problem with my 350. I'm running a 750 holley, .469'' lift/268 dur. cam, headers, 2200 stall conv and 3.08 gears in a regal. If I give it WOT off idle it goes flat for a couple seconds like it's going to stall, then wakes up and spins the tires. I've tried setting the timing anywhere from 10*-20*, changed power valves, pump shooters, sec springs, jets, adj fuel mixture, pump arm, and cannot cure the prob. Car does not stumble or hesitate and any other time than off idle. What the hell is going on here? Please help.
Sounds like a carb problem. I have been tinkering with my holley and have had situations like that when I had the wrong power valves. Have you checked the vacuum yet while in drive? Maybe the power valves are the wrong ones?
Were is your vacuum source for the distributor? Some combo's don't respond well to manifold vacuum. When I did my motor swap in my truck, I had a similar problem. I used the timing light and gunned the engine and the timing retarded for a second or two before climbing. I switched it to ported and never looked back. There are people who insist it should always be manifold vacuum, but Ive seen combo's that work both ways. Also, check to see if your advance is working at all.
Vacuum advance is run off ported source. Vacuum in drive is 12.5; have tried 10.5, 8.5, and stock 6.5 power valves. Could it be that I need lighter advance springs in the dist to bring the timing up faster? I'm out of ideas.
