what you intend on sticking it in, and what you intend to do with the vehicle makes a big difference in what cam and stuff you want to do. there are a bunch of vortec head specific stuff that you have to do. a carb will require that specific adapter manifold. any cam .4 lift needs aftermarket springs they say. alot of times you will be better off performance and price wise selling the vortec heads, getting standard aftermarket sbc stuff. some good aftermarket heads like afr, are worlds ahead of any stock gm stuff, and all the available parts that you need to go with it are way less money because its less specific to one combo.
1998 Bonneville SSE
2007 Monte Carlo LT-KYB, Clarion, Polk audio, Kicker
1999 Yukon SLE-KYB, Air lift, Reese dual-cam, Tekonsha
1987 Firebird-355/th400-nothing stock