318 into a 340

can't tell you on the poly. i do know that the 318 poly engines were in the 61-65 range i think?. just keep the 318 with the 2.02 heads , do a small overbore for compression 9.50 to 1 (89 octane pump gas) or so and maybe stroke it out alittle. that engine is able to crank out some good power with not alot of work.