What's the real story with vortec heads?

Scoggin-Dickey says they can't take over .450 lift, but they want to sell their modified heads with Z28 springs and LT4 retainers.

GMPP uses a .435/.460 lift cam in their 350HO crate motor.

Chevy High Performance says max of .470 lift.

I want to use Comp Cams 265 Dual Energy .442/.465 lift or XE262 Xtreme Energy .462/.469 lift. Will either work?

What cams have you people been using with Vortec heads?

Thanks,
Joe

PS Is it the springs or the guides that limit valve travel? If guides, can they be hand worked a little?


[Modified by joe73vette, 10:17 PM 11/14/2002]

 

[QUOTEChevy High Performance says max of .470 lift.[/QUOTE]

Thats not what they say in the Jan 2003 article. "The stock springs will only accommodate around 0.420 inch of valve lift".

I can see why you're confused. Check out the article though, it should hopefully answer more questions then it raises.

 

I'm using Vortec heads (12519093; https://www.spoperformanceparts.com/) on a 383 for my Bronze 84.

See Vortec Head assemblies (p/n: 12558060) for Technical Notes.

I'm using CompCam's (LT1 XR269HR-12 grind, p/n: 07-502-8). It has a gross lift of 0.495 Intake, 0.503 Exhaust.

Valve bind is a problem with the Vortec heads and this much lift, the maximum camshaft lift is .475". To avoid cutting the spring pockets Crane Cam 99846-16 springs are used.

Crane Cam technical notes---> "The 99846-16 springs are made from H-11 Tool Steel and provide open pressures of up to 350 lbs. at 1.175" open height. These "stock diameter" springs for small-block Chevys can be installed in stock spring pockets without machining or removal of the cylinder heads. Stock spring retainers can be used, but we recommend our Crane steel retainers and machined steel valve locks for maximum strength. The 99846-16 spring is engineered to handle up to .585" gross valve lift .... " http://www.cranecams.com/master/vsprings.htm

BTW; GM Performance Parts is having a "Garage Sale" until the end of the month.
http://www.gmgoodwrench.com/dhtml/pa...ragesale.shtml

Many parts are on sale: 355 hp ZZ4 5.7L engine, the ZZ502/502 Rat; the bare Vortec Heads (p/n:12519093) are $206.17 each; the Vortec Head assemblies (p/n: 12558060) are $245.06 each.
:cool: :chevy


[Modified by torqueman2002, 2:35 PM 11/16/2002]


[Modified by torqueman2002, 2:37 PM 11/16/2002]


[Modified by torqueman2002, 2:38 PM 11/16/2002]

 

I agree...what is the actual lift capability!

The magazines have royally screwed up the facts on this one...:)