What are the differences? I know The vortec heads are ported and polished, but what else? roller rockers and lifters? better springs? Whats the hp/tq difference for a 350

 

The Vortec heads have higher than standard intake and exaust ports which require a special Vortec intake. They have a very efficient combustion chamber. They need self aligning rockers because they don't have guideplates. They don't have roller rockers stock.
There are a couple of difference to older style heads. There are 3 iron '86+ 350 heads that I can think of that GM used, 4 if you count the aluminum L98/ZZ4 heads.

Vortec heads should be worth about 30HP over L98 heads because of better ports and combustion chamber. The downside is that Vortecs are too thin to be ported out. I've seen ported L98 heads flow more than new fast burns.
the GM 350 H.O. is rated at 330HP with vortec heads
the older GM 350 H.O. was rated with 300HP and had the non swirl port heads.
the other GM 350 had the swirl port heads used in the L05 and was rated between about 195HP and 210HP. These comparisons don't include the cams so just use them as a base point.

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-Tas
'89 Formula WS-6

305, TBI, auto, 14x3 chrome flat based open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips....

Soon to be installed:
Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248), Catco 3" cat, and injector spacer.

Super GRK_Taz World
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Tas, you don' thappen to know the casting numbers of the heads you mentioned, do you? Not the Vortecs, the other two... Got a line on a bunch of heads but talking to the guy on the phone. Want to match the casting no's before I take the trip.