The only difference i see between the motors that Jimmy and i have to your motor is the compression ratio, with my 406" i had 12.5 to 1 with the track1's and Jimmy has 52 CC heads with flat tops, so his compression is probably close to 12 to 1. The 377" i have in the car is 14 to 1.
Don't know but compression might wake it up, that would be the cheapest way that i can see, around $500.00. If you have some scales you can match the pistons to the weight of the one's you have in the car without having to rebalance the crank/ whole engine.
Your heads are almost the same as i have except i have 58 CC chambers and 2.140 intakes, which will make my 434" about 15.5 to 1, but it's will be on alcohol stacks. I surely hope i don't get surprised with them (heads)
not working good. I am running a much bigger 4/7 swap cam in it.
Zip.