318 build suggestions?

i can't comment on price for the short block because there's not enough info.

as to the rest, it sounds like you're building a blvd brawler, so street manners are [mostly] out the window, which is good... because you need a pretty rowdy cam to get were you want to.

the magnums *seem* like a good choice, but once you put the money into machine work and porting, plus the valve train and some roller rockers you could easily be at trick flow's which are a straight bolt on and go, and the options for roller rockers are much better/cheaper/available.

personally i'd go TF's with an eddy airgap. top it up with your choice of carb in the 750ish range. then select a cam based on where and how you want to make power. probably something in the 500 lift range and 280+ duration. a roller cam will absolutely stomp, but that's a good bit of dosh to splash out. don't cheap out on a timing chain.