Re: Wrong info....Vortec heads
For the EGR, you will need to run a return tube from an exhaust manifold/ header, to the intake manifold. Edelbrock makes them, and they come along with a kit they make for the vortec conversion. Your centerbolt valve covers still work, yes. You also asked about rockers. Your stock rockers will work just fine. If you want to upgrade, I would go to a 1.5 roller, or 1.6 roller, either from Crower or Comp.
You were also asking about $$$$. I did my whole motor, heads, cam, intake etc, for about 3,000. This was after going through all the incidentals. I know it sounds like alot, but not after factoring in all the stuff I did. I got stainless braided fuel lines, headers, and numerous bolts, hoses, etc. All new stuff to make sure everything was ok.