12 second 340

Adam, You have a lo com. 340? What about getting a set of Cometic head gaskets to bump the comp up. Slide a new cam in, and get some 4.30s? Those Cometics are pricy but are reusable. Should be a one time purchase. You will need a 750 carb.
Call Don @FBO 503 627-0728 he sells them and he could help you figure it out. Mike should call him too to figure out his problems. The guy runs a 318 with 1.81 intake valves in the 11.70s He knows his stuff and is a real nice guy.