liteumup387

hey everyone im looking to start building my 350 tpi out of a 91 z28 and im stumpd i cant decide on a set of heads the cam im using is the powermax cam
(lift .509 .528 duration 284/292 rpm range 2000-6200) so whats your opinion on what heads i should use i should mention that im not looking to spend $2000 on a set of heads really the cheaper the better.

Rydda

vortecs are the way to go. but you need to have some head work done. because stock the vortecs are only good up to .500 if you get the heads from a bone yard, you can get them for a couple hundred dollars, then to have them milled, a three angle valve job, screw in studs installed and i believe its the valve guides need cut. i could be wrong on the last one, but i know something needs cut. just tell your machine shop what youre doin and they'll know what to do also they will hot tank them and check for cracks. this will cost between $300-$400 depending on shop costs and what state you live in. i did every thing but have the cutting done and it cost me $300 at a local shop. or you can go w/ double hump heads, they dont make as much power but they are still very good heads, and in most cases you can get them w/ most of that work done. if you get double hump heads make shure you get either 461 or 462 castings and not the 291's. effectively they are the same heads, but the 291's dont have the bolt holes for the accessories (alternator, power steering ect.) as where the 461's & 462's do.

liteumup387

ok thanks man ill check out some machine shops n c what they say... any other suggestions

madcow69

With that big of a cam you're going to need to do some work to the Vortec heads to get proper valve guide to retainer clearance. There's only approx. .460-.480 between the bottom of the retainer and the valve guides. Add in the .060 reccomended cusion and you can see that only near-stock cams will work safely.

Also the Vortec heads flow peaks at around .480 lift. Anymore lift than that and you're actually hurting your flow. So you might look into getting some port work done.

New Valve Springs are also a must. The stock vortec ones are meant for wimpy truck cams.

Also i'm not totally sure on this becuase i'm running a carb with a vortec-style intake on mine, but I think you have to change your intake or maybe get an adaptor to get it to bolt up to the Vortec heads. I'm sure searching around would give you more information on that.

I know this seems like alot of work to do for just a set of heads, but Vortecs are worth it especially when switching over from an older style head design. To give you a point of reference, these heads outflow LS1 heads until .650 lift.

Vortecs are going to give you the best performance per doller out of any head out there.

OutLaw305

Just for a little clarification...

Hasnt there been more thna one style of vortec heads produced? About 2 years ago I bought a crate engine which had Vortec heads on it. I was concerned at first because I had heard of problems with the design, but I was informed that these were the re-designed, new verison of the vortec's.

As of now my only concern is that these new style heads have pretty large chambers (70CC) and IIRC this reduces compression. Am I correct in stating this? Further, if anyone knows, what are the pro's and cons to these heads? I forget the specs on my cam, but im running those aformentioned vortecs with a Performer RPM intake and pushing 360hp/380ftlbs off the flywheel dyno. Im lookin for more lope out of that cam, but am worried about going with a longer duration when I dont know how those large vortec chambers will come into play.

Any ideas?

Wadebryant

Here's a one stop / shopping package deal...just what you're looking for..

From Scoggin-Dickey. Part # SD8060RATPI Vortec .575 lift heads, TPI Vortec intake and all of the misc stuff you'll need for $1309.95 + shipping

Check it out at http:Scoggin Dickey at Sdpc2000: Performance Parts, Racing Engines, Racing Engine Parts, Race Engines, Race Engine Parts - SDPC

Happy hunting

madcow69

Outlaw there are many different versions of the Vortec heads out. RHS, Dart, and Edelbrock all have their own versions of the 'Vortec' head. GM Performance Parts also has a few different versions, like the ZZ5 Vortec head that comes with a a max lift of .550. There are also the small and large port Bowtie Vortec heads.

As far as a 70cc chambers go it sounds like they cleaned up the combustion chambers some. Vortecs are very good from the factory but can use some port work around the exhaust valve. That's what I believe happened in your case.

Check the casting number on your head. If they're 062 or 906 castings, then they're considered 'stock vortec' and have had some work done to them to accomodate the cam.

lilbowilson

iTrader: (2)

Well since your trying to save money I would buy a set of vortecs from this guy:

eBay Motors: Small Block Chevy Rebuilt Vortec Cylinder Heads (item 160044728697 end time Nov-01-06 12:34:55 PST)

He says he bowl blends them and puts a 3 angle valve job on his rebuilt vortec heads.

But if I were you! I would save the money and get Dart, Trick flow, Brodix, or the all powerful AFR heads! I've owned vortec, TFs, and AFRs and the vortecs just don't compare to a good set of aluminum aftermarkets!

madcow69

While I agree with bowilson that a nice set of alluminum heads would make more power, they're nearly twice as expensive.

Also i'd be carefull of any port work done on Vortec heads. Too much and it can remove the flow effect that makes these heads flow as well as they do. If you were going to do those ebay heads, you should check into that guy and see how much of those heads he's actually done, and see if he can provide any flow numbers.