I've got a 91'Z28 with the 5.7. will the aluminum heads from a vette bolt right on?
Will the headers fit my stock cast iron heads?

 

They'll bolt right on but I think you won't have EGR thus fail emissions unless you switch over to a vette intake manifold.

As for your header question, I'm not sure. But I know SLP headers will fit

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91 Formula
305 TPI 5speed
1LE/G92/WS6

Paxton SN92 polished kit, SLP airfoil, ported/polished plenum, March pulleys, Crane AFPR(43psi),Crane Gold 1.6rrs,MSD coil,MSD6AL,MSD boost-master,Holley 9mm wires,Ac delco R43ts plugs,custom chip,Ford SVO 24# injectors,Bosch O2sensor, Bosch in-line pump(w/stock pump), SLP 1 5/8" headers,SLP catback,short shifter,3:73s w/Auburn posi,170* t-stat,JET 195* fan switch, Macewen white face gauges, Autometer gauges, Zoom hi-performance clutch.

 

they will bolt on but as suggested, EGR will be inoperative. My question is why? the only thing you'll gain is less weight because the heads are basically identical besides material and the lack of EGR on the vettes. I wouldn't waste my time, upgrade to Vortec or aftermarket heads. the headers would fit the heads but not the car.

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Kyle Osterholt
Okarche, Oklahoma
ASE Master Certified
86 T/A 383 TPI
89 TTA #1002 T-top/Leather
89 TTA #1358 Hardtop/Leather
80 T/A Pace Car
73 Opel GT
73 bronco

 

Why? Because they're a decent head for less than $1000. Especially if you find them for less than $500. I love mine, but they need to be ported to make them more effective. You'll also need new springs if you run a cam over .500" lift.

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West Coast GM Shootout 2001!
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

Thanks for the input guys, I'm going to keep the stock heads, but have them ported and polished. It's nice to hear the opinions of people who aren't trying to sell you something.

 

for less than 1k you can get a lot better heads. A set of Vortec's will spank the vette heads for around $400 or cheaper if you get lucky. Canfields, Dart Iron Eagles and some other heads are also less than a grand and a lot better heads. Then you have the Edelbrock and Trick Flow aluminums for around a grand or a little more or you can step up to AFR's for about 1300. Unless the vette heads are given to you, they really aren't worth the work because basically you're only losing 30 or 40 lbs and not gaining much, if any power.

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Kyle Osterholt
Okarche, Oklahoma
ASE Master Certified
86 T/A 383 TPI
89 TTA #1002 T-top/Leather
89 TTA #1358 Hardtop/Leather
80 T/A Pace Car
73 Opel GT
73 bronco

 

Vortec heads also need to be redrilled and modified to work with regular intake manifolds, so there's extra cost involved. My heads were given to me, and my dad ported them, so I got a great deal. They are decent heads, but like you said, you can spend a little more money and get something better out of the box.

 

Let's get some more discussion going here. Answer one question for me. Why is the Corvette aluminum head used exclusively by Lingenfelter? Does he know something we don't?

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Willie

Supercharged 1987 305 IROC-Z, Daily-Driver, Emissions-Legal.
Paxton (6-psig): 12.57 @ 111 mph.
Paxton (6-psig) & 50-hp nitrous: 12.04 @ 114 mph.
ATI D1SC (10-psig): ?

http://willie.camaro-firebird.org/

1987 "20th Anniversary Commemorative Edition" Z28 Convertible -- Super Chevy Show Class Winner, 1998.