whats the point of the 318 block is it the shared stroke with the 340? I believe its a 3.91 bore that cant be taken to 4.0 correct? The only advantage I see is traditionally a 318 was laying around free or cheap i bought a LA 318 with a 904 bolted to it with every thing from carb to linkage to exhaust manifolds for $40 delivered that was 20 years ago though.