good info.

I have always thought a 318 should be as good as a 340. it is just lacking 22 cubic inchs and cam/heads/intake/carb. with my 318 with a 3.970 bore 3.31 stroke @ 328 cubes I am only 12 cubes short of 340. so I can go to 4" bore 3.31 stroke for a 333 cubic inch. now I am only 7 cubes shy of 340.

IIRC a poly318 & LA318 share a lot of parts. (steel crank-float pin rods-pistons-timing gear/cover) so a .090over poly piston I looked at has a 1.8 CH and have a better comp ratio than a stock .060 OEM LA318 replacement piston @ 1.7CH and it is in the cheap OEM cast piston price.

so 4" x 3.31 = 333 cubic inches(steel crank/floating rods.4" poly pistons 1.8CH

bump my 1.88/1.60 J heads up to 2.02/1.60 valves with a little bowl work/clean up

then it would be about cam choice. it should buzz well past the 5500 mark with the right cam choice. I would be looking for 6200-6500 with a 4 speed.

is it worth the effort? I would think so.