The "Throw Away 318"

318 or 340 pistons and rings being the main differences in costs, what is the reciprocating weight savings? A set of 318 pistons and rings will weigh less... and then if you balance the crank and remove weight out for the 318 piston set, its even lighter.

If you max port the heads and use the same cams, at a MAX build of both engines, what is the HP ratings? Maybe the maxed 340 will make 20 to 25 more horses but the 318 will rap a little quicker.

A free 318 short block VS a $1000+ 340 block is the main argument here for some.
That $1000+ will go a long way on that FREE 318 block.

Someone that is PRO 340 will always find some argument to support their feelings. ;) But if you give me a 340 block I'd make a 426 stroker out of it.