Wow, you're going to have fun turboing that engine. Besides the turbo(s) and a BOV, there isn't much you can get at a junkyard for it. Are your exhaust manifolds easily convertable for turbo use?

I wouldn't run over 8 pounds on that engine, just because I don't know what it can take.

Boost gauges tap into the intake side. It's a either an electrical sender of a vacuum line, easy as pie.

Electronic boost controllers are much more presise, and programable. Not to mention about $400 more expensive.