What are the diff's between the ZZ3 and ZZ4 heads? Different valve springs, rocker arms,...?

Lookin for a set if anybody's got some new take-offs.

thanks
Jeremy

 

pretty sure they both use L98 heads, just the zz4 has a different cam and a low rise intake

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91 RS W/carbed 350, Vortec heads, performer rpm, Comp cams Xtreme energy 280 grind. BFG Drag radials. 3.42 posi,Corvette servoed 700r4, ****ty stock converter
13.24@104

 

Here I thought the ZZ3 and ZZ4 cams were the same, the difference was in the piston and rod materials. Heads were the same, I thought, like vortecfcar said.

Why would anyone take the heads off a new crate engine? If all you want is the short block, buy that.

But, stranger things have happened.

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82 Berlinetta, orig V-6 car. Rescued w/86 LG4/TH700R with all harnesses, sensors, ECM, etc. 2.73 open. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LB9 w/ZZ3 cam, exhaust, paint, etc.).
57 Bel Air, my 1st car. Currently 396 .030 over, Weiand Action+, Edelbrock 1901 Q-Jet, Jacobs Omnipack, 1-3/4" headers, TH400 w/TCI Sat Night Special conv & shift kit, 3.08 10-bolt, AMSOIL syn lubes bumper-to-bumper. Best 15.1 @ 5800' Bandimere. Daily driver while Camaro was being put together.

 

Microge Warfare (Germ),

I believe they both use L-98 Corvette heads that are 58cc.

Flow benched at .500 lift at 196 cfm intake and 170 cfm exhaust. Chevrolet has made worse heads.....lots worse.

Port and polish, add 1.6 rockers on the intakes, and boogaloobie.

BOR

 

The ZZ4 and ZZ3 heads themselves are identical. Aluminum L98 Vette heads.

The ZZ4 heads got new lightweight valvespring retainers and ovate wire valvesprings yeilding more seat pressure and increased coil clearance (I believe these were LT4 parts, not sure).

Never been a fan of the L98 heads myself, unless it's a 305 buildup...

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Ray87Z
-Vortec headed 350.
86 IROC w/ a cammed 305 TPI.
Formerly Ray86IROC.
www.inter-scape.com/Ray

 

I looked in the GMPP book and the cams are different

 

The ZZ3 and ZZ4 engines used the same cam and heads. The valve springs on the ZZ4 heads are the same as in the LT4 HOT cam kit. I believe the ZZ4 has a different crank too. There is something else I'm not remembering that accounts for the 10 HP difference.

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1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
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