71 340 head choice (budget)

I can get heads done cheaply, but as you note - cost and quality are tied together. If this is "the last engine" for this car, you might want to save a little more up and get high quality work done. In this case I'd run LA based heads. Not the Magnum stuff. IN terms of Comp stuff- I run a lot of it. The XE262 is in my truck. I think it's a good cam to run, and the Comp runs the cheap 901-16 spring. Another nice cam for a mild 340 is the High Energy 268. That will have some bump in the idle but I ran it for years and passed emissions back when I still had to.