Early 318 blocks

I totally agree with this statement, I practice this myself. If however some of these blocks are as I've heard and can take a 4" bore while still maintaining acceptable wall thickness, they are then an affordable block for those of us with forged 340 main cranks.
A standard bore 318 will gladly accept your forged 340 crank also...I get that guys want a "cheeper" 340, but it's not the best idea in the world