I have a 402 I just installed with a 280/288 lunati cam. I have an msd igniton and 750 holley vs. When I start going over 3000 it starts missing or popping. I have the valves set right, timing at about 14 with about 36 in by 3000. The carb is all stock. Vacume gauge reads about 12 at 800 rpm. Would not enough timing cause this, wrong power valve or jets maybe? Any ideas would be appreciated. Thanks, KJ.

I'd jet up. A bigger cam wants more fuel along with the extra air.

I figured it out it was the the distributor moving on me. I had it pretty tight but I guess not tight enough. Reset the timing and made sure it didn't move on me and doesn't miss now. Thanks for the reply Pat and I'm gonna try a little bit bigger jets and change the power valve to see if I get more out of it. KJ

If you have a chrome hold down, it will be a continuing problem. Get one from the Chevy dealer and solve that problem. smile.gif .

or just use some 80 grit on the bottom of the hold down and that should keep er tight.

Originally posted by 1ss427:
or just use some 80 grit on the bottom of the hold down and that should keep er tight. My experence with them has not been slipping per se but bending to the point that they will no longer hold the distributer.