GM Performance VS Summit vortec heads
 

http://store.summitracing.com/partde...=KeywordSearch
GM Vortec heads $260

http://store.summitracing.com/partde...=KeywordSearch
Summit Vortec heads $350

Basically they are the same, same valves, but summit heads have a 175cc runner whereas the GM heads have 170cc runner, why such a huge price difference and would the GM heads be a nice investment?

The summit heads are noy factory GM heads. You might want to call them to see if they are already setup for higher valve lift, unlike the stock vortec which are limited to about .460" lift. If i had to guess i would say that they are but, i really have no clue.

I had the same question. The Summit's are good to .520" lift and intake runners are 5 cc's bigger. Also they are 67 cc compared to 64 cc. Not sure if that necessarily means they'll make more power than the Vortec's.

How about these?

http://store.summitracing.com/defaul...9822&x=41&y=10

Those last ones are the newer Bowtie Vortecs from GM, and that price is for the bare head vs complete heads above. It's a higher perf head for certain racing classes I believe. I'm not seeing how they're worth it for most standard use however.

I don't know anything about the larger intake/combustion chamber Summit vortecs, midly ported w/ a valve job it sounds like but I'd be real skeptical what the real details were on them (description ain't giving you much to work with) and whether they were worth a crap or not without flow numbers or something... Course they're about the same price as most any of the Vortecs with the spring/lift upgrades already done (which this doesn't state they have, but surely... Again more details needed...)


EDIT - My newer paper Summit catalog has more details on the SUM-151124 Summit Vortecs, it adds:
Sounds like they don't really flow any more than the stock Vortecs, but they're setup to handle more lift... Still needs self aligning rockers I believe since they don't have/aren't setup for guideplates even with the screw in studs.

My thought was possibly for a larger cubed motor.

Sounds like they flow slightly less than the GM Vortecs. Don't they get about 240 cfm at .500"?

This may be a dumb question (and if so, I'm sure someone will tell me) but you are aware that there are several different part numbers for the Vortec heads, right?

Here's something out of the GM Performance Parts catalog, which is quite a bit different from what has been noted in the posts above:

25534431 Vortec Bow-Tie Large Port Cylinder Head, Complete
GM Performance Parts' latest and most powerful iron cylinder head with "Large Port" for Street or Racing. This Vortec design Special Performance cast iron cylinder head features revised intake and exhaust ports and includes 2.00" hollow stem intake valve P/N 12555331 and 1.55" sodium filled exhaust valves P/N 12551313. The deck surface is .450" with 65 cc combustion chambers, 206 cc intake and 77 cc exhaust ports. All Vortec intake ports are taller and narrower than early model Chevrolet heads. The valve cover mounting holes are for both early model flange and late model center. This head also includes intake manifold mounting holes for both early model 6 bolt main and late model 4 bolt Vortec design. The head has screw in rocker studs P/N 12552126, large valve spring pocket machining, and will accept up to .530" lift camshafts without modifications. Heads are identified with the Bow-Tie logo on the exterior of the head below exhaust flange and Vortec logo on top of intake port area. They also feature GM logo cast into bottom of intake ports. Includes valve spring P/N 12551483, valve seal P/N 10212810, and spring cap P/N 10212808.

There is really only two true vortec heads the 906, and 052 350 truck heads.

All those others are just performance based heads cast by gm. GM just applied the vortec name to them because "vortec" is a very valuable and well known name.

So did anyone find out if these summit vortecs are any good? Looks like you can get a complete set for $600 now!

In another thread I thought someone might have mentioned getting a set of the Summit heads and they had Pro-Topline cast into them. If they are in fact the Pro-Topline head then they are a better casting then the stock GM castings. Thicker decks, machined for higer lifts, better coolant ports, flow better than stock, etc, etc.

I know this is an old thread, but to put the question to rest, I just got my Summit Vortec heads and they have Pro topline cast all over them and Summit didn't even rebox them, came in a pro topline box. Look to be made very well for the modest $650.

Ooops, didnt noticed this was an old thread.