I made the mistake of putting some 360 heads on a 318. The combustion chamber on the 360 head lowers the compression ratio on a 318. Car was a slug down low. Pulled fine up high but it was a mistake. At least rhat was my experience.
I did the same thing but had a 292 erson cam with stock converter and stock 2.45 gears and a 28" tire wow! It was horrible!! After 3,000 it pulled pretty good.