This is a newly rebuilt 440 Challenger with a mild roller cam, 4 seconds flat distributor, headers and 4 speed. I know you guys are going to tell me to use a timing light, but - I like to try and find the best seat of the pants performance just by moving the distributor in small steps around my "sweet spot". I've got a mark on my distributor and on my block.

So this is what what happens. If I keep advancing the timing past my sweet spot - the car will not ping at full throttle, but the idle gets rougher and the car bucks back and forth when I'm trying to cruise around at 30 or 40 mph in 2nd or 3rd. (Is this "surge" like in VCODE's recent Thermoquad post?)

So I'm trying to get my distributor sorted out before I start fooling around with my brand new Holley 750 vacuum secondary. My problem is, the car doesnt feel as strong as it should. Should I go back into the distributor and move the limiter plate to allow more advance? Should I really follow FBO's directions and plug the distributor into a constant vacuum source, which doesn't make sense to me?

thanks in advance! John