Hey Bran,
I have a mild 9:0 to 1 pistons,460 with 280 comp cam. I run a msd 6al and accel distributor with 12 degrees of vacuum advance. The vacuum at idle will get rid of the stumble. I set my initial timing at 14 degrees and mechanical springs at 24 degrees, so 38 degrees total timing and another 12 of vacuum at light throttle/cruise which drops off under W.O.T. I have no problems with pinging running 92 super chevron.
Perry.
