Street 340 heads/cam recommendation?

You choke the 340 with 302 heads. A close chamber head will limit your piston choices, the kb hypers which are $250 sit .018 out of the hole.

A good cheap build would be the kb pistons and late 70's early 80's 360 heads. The earlier 68-75 heads would be a little better. Heads you can spend lots of $ on.