The biggest valves factory installed in 305 heads is 1.84 intakes and 1.50 exhausts. I am not positive but I dont think the TPI heads are the swirl port ones...if not, you will see no gain swapping heads (they may in fact be the same castings). Vortec heads require a dedicated intake as they only use 4 bolts per side, and the bolt angles are quite a bit different. You can get a vortec pattern performer, performer rpm (hi-rise dual plane), 2bbl victor jr., and a super victor from edelbrock. GM also sells vortec pattern intakes for TBI and 4bbl's. As of yet, I dont know of any TPI vortec base, but they may be out there.
'78 chevy truck-355, 9.4-1, vortec heads, XE268, vortec rpm intake, 750 edelbrock, flowtech headers and terminators.
'77 Nova-slowly progressing project.
'78 Nova-parts car?
'95 Lumina 3.4L DOHC 210hp daily driver