DrVette, I think you misunderstood the reference to "a carb intake and an adapter"- he meant to use a carb intake w/a
TBI adaptor to use the OEM EFI set up.
One difference in the exhaust manifolds between the TBI and Vortec engines is the Vortec manifold has a provision to run exhaust up to the EGR valve. I'm unsure if that's what was being referenced or not, though.