340 street build with timing questions
 

What is reccorecomm base timing with a 472 lift, 260 duration and 11:1 comp, thunder series 650 Edelbrock carb and a vacuum advance Mopar distributor?
im getting back break up under heavy load, throttle, at 2500 to 3600 then it Roars.

With todays fuels I would start with about 15deg btdc vacuum advance disconnected See how it runs. You may need to modify the distributor

Problem solved.
 

Pinned the vacuum advance and set base at 12 btdc.
trans has manual vavle body and was starting in second gear.
Car hauls ass, gets sideways in second, good idle and street characteristics.
Total advance about 34-36, no hesitation and good plug reading, no detonation.
Thanks for your replies!