Vortec heads require an intake that will only fit the vortec head. The vortec heads and the intake will fit a sbc, even older model 350.
I'm using a set of vortec heads and an edlebrock rpm perfomer intake for the vortec heads on my 350 that is going into an'82 model chev p-u.
The articles i've read indicate the vortecs flow as good or better than the double hump heads without the need to port. All the bracket holes are the same as my 82 p-u so a/c power steering and alternator all will bolt up.
Hope that helps.