Tuning For Detonation

Dave_J said
Seems to my memory from the 70's, brain cells wasted, that the early \6 had Vacuum RETARD, not advance.
With the crappy 'Reverse' flow head and pisspoor quench the guys at Ma Mopar said you can not run these engines in Advanced timing.

I played this same game as RRR is doing way back in the 70's and gave up on advancing timing.

I also did a piston stop check on my last \6 build and the timing marks were off 7 degrees, advanced from true TDC. The dampener had been replaced some time in the past. I marked correct TDC and put a DC's timing tape on it.

I also suggest turning the carb 90 degrees so the two primary's are feeding evenly. The long front runner is getting a fat load and the rear long runner is lean. By having both primary's up front you exacerbated this miss match front to rear flow.

I've never known them to retard timing with vacuum.

Be that as it may, you're right about the early chamber. They sucked. That could be some of the why. Although, with 175 PSI I kinda think that was most of it. But surely, a more efficient chamber would help. And no slant six ever had any form of quench. There was what they called a "revised" chamber in 68 I think it was, but there was no quench involved. Not with the stock piston at least .150" in the hole. lol Ain't happenin.