On the poly 318 you change the cam, heads and intake to the LA and bore it to 4.040. You now have a 340 with 318 numbers on the block. Yes it can take that big of a bore.
Is that even possible? I have NEVER seen a poly with a "LA" top end....Have you done it....... or is this one of those I know a guy, who knows a guy, deals? Id rather have a stroked crank in a poly personally.