From personal experience, the vortec heads are great...huge power gain over my previous set of ported 882's...however, heres my thoughts on this. If you are starting out with a stock intake (or plan on stepping up to a better aftermarket intake) and also plan on upgrading the rockers, then the vortecs are a heck of a deal. The $400-450 price is a bit misleading though because you will need a vortec intake ($160-180 for performer/performer rpm), guided rockers ($50 for new gm stockers, $130+ for aftermarket roller tip/full rollers), centerbolt valve covers ($50 for new gm stockers), the special intake gasket ($26...but it is reuseable and is the best intake gasket design I have ever seen for any engine), plus the assorted misc. pieces (intake and valve cover bolts and centerbolt vc gaskets). If you already have a performance intake and some nice stock or aftermarket vc's, then I would look more at an aftermarket head like the trick flows. Besides, if you plan on using a cam over .460 lift, you will need to upgrade the springs on the vortec heads, and the aftermarket heads normally come with good springs. I love the performance of the vortecs, but if I would have investigated a bit more I would have used aftermarket instead.
One other thing...vortec heads are pretty well maxed out from the factory...supposedly they dont respond much to porting or performance valve jobs...so if you plan on building something pretty stout you would probably be better off performance wise to go aftermarket.
375hp 78 Chevy truck
77 Chevy Nova
95 Chevy Lumina 3.4L
and building a 78 Nova
[This message has been edited by travis (edited 03-29-2001).]