Oh dear God! 318 stroker

I would start with a Molnar 3.58" stroke crank for a 318/ 240 main with 2.100" rod journals. This opens up lots of choices on rod length (anything from a 6.00" to 6.500") and more

common .927" wrist pin pistons. Then it's just a matter of selecting a piston compression height that will work with one of the available rod lengths and you can get in the cubic inch

range you wish to be in. You just need to know your deck height (I am guessing 9.58"), what CC heads your planning to use, and the compression ratio you would like the engine to be.

Tom