Their is a cast crank for the light rod 318 with no holes in the rod journals. Then there is a cast crank for the heavy rod 318. This crank has a hole in the front and rear journals like a 340 crank. Both 318 cranks are neutral balance.
Hunh... I have been wondering how they compensated for the rod weight change; the bobweight changed by 45 grams from light to heavy rods. That makes all the sense in the world, Kim. Thanks.
I see the places like Crankshaft Supply only sell one 318 crank for all years, so I assume it must be the one with the holes in it.