Even though my other interests are distracting...
Which of the "HO" 5.0L go fast parts will bolt up to my non-HO 5.0L. I've heard the GT-40 stuff would, but what else works?

 

heads, intake and rocker arms. Not much else. The H.O. is a roller engine, and has a different block and valvetrain than your engine does.

Take care,
-Chris

 

The heads are the same(unless the engine is out of a mustang cobra). HO engines have forged pistons and a roller cam with a different firing order. They also have a different intake than a truck does and come factory with headers. I recently swapped a HO motor into my 92 and used my truck intake, and it is quite a difference.