[AJ-]

I have an 8.5:1 (calculated) 400 with 6x heads and a 213/218 cam with .450/.467 lift (with 1.65 rockers) and a 114 lobe separation. I am trying to get the timing dialed in. I originally had it set at 31 degrees total timing just to be conservative as a baseline and had planned to bumped it up a bit at the track to see what it liked. Long story short it was a busy night and my first few passes revealed a few other issues to sort out so it wasn’t until my last pass that I got a cleanish run in. I never got a chance to play with the timing.

Anyways, my main question is about vacuum vs mechanical advance. Since then I bumped my timing up to 34 degrees total timing and I think I noticed a very slight amount of detonation while going up a steep hill at fairly low rpm. Hardly noticeable, but pretty sure it was there. My mechanical timing comes in really quick--it’s at 31 degrees already at 2000rpm. The vacuum advance at 2000rpm adds in another 13 degrees. At idle it adds in about 16 degrees.

First question: What should I do, slow down the mechanical advance curve, limit the vacuum advance, or both? I was thinking of limiting the vacuum advance either way as it sounds like around 10 degrees is ideal but I don't know if the curve is also an issue.

Second question: How much was I leaving on the table at the track with my total timing at 31 degrees? I ran a 14.34 @95mph. I was also having some cooling issues with a hot day and a long line to get into the track and long staging lines. I was running around 210-220 degrees on that pass. If I could be closer to 190 degrees would that make a noticeable difference? Rest of the combo includes quadrajet, th350 with stock converter shifting around 4600rpm in drive, 3.42 posi rear, stock log manifolds w/2.25 dual exhaust. Minor tire spin at launch on this pass. I’m pretty happy with the performance for what the motor is, but dipping into the 13’s would be awesome.