318/360 heads,with thumper cam

A couple of quick questions. Is the 650 carb you have access to a spread bore (secondaries larger) or a square bore(primary and secd. the same size)?

And do you want to leave the shortblock untouched as it sits if possible?

To get to your desired power level, the compression will have to be optimized. trying to figure out the best way to get there for the least amount of time and money will take some thought.