Quote:

My 70 340 ran best with 32 degree's with the 509 if the 509 is old it is a racer brown model I'm talking mid late 70s. The Comp is definitly building more cylinder pressure. Have you tried 30 total and or racing gas? at least 100 octane? Just curious, I also had 340 do the same thing and it was the valve springs but I would check the timing before going threw the hastle



I was caught off guard by the problems so i went up in timing instead of down and had no access to race gas even if I thought of it but I think you are on to something