Boham92RS

Does anyone know if the 3.1 and 2.8 heads are the same? My friend has an 89 z24 and one head is shot, so he is looking for a set of heads to rebuilt or already rebuilt ones. He found a set from a 3.1, but Im not sure if that'll work. If not.. anyone got some heads from a 2.8 they dont need?

RenoLB8

I've got some 2.8 heads I'm perfectly willing to sell, but they're RWD, so I don't know if that would work. From FWD to FWD, 3.1 and 2.8 heads should be interchangeable. If you find out mine will work, email me.

-Reno
Reno9114@aol.com

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'88 Firebird LB8
"Cerberus"
-Supercharged Hybrid LB8/L32 Project-
"Got a green light, got a red light, no cop, no stop, man I don't care, every one of you could be the same, every one of you could play this game, got a green light, got a green light but you're going nowhere..."
http://www.angelfire.com/il/Firebird28/index.html

Red91Bird

The aluminum heads can not be interchanged with iron ones, and vice versa. I am pretty sure thats the difference between the FWD and RWD... FWD = aluminum --- RWD = iron. or atleast thats what i have found. The piston deck height is different between the two and you will smack a valve if you try to use a different head then what it is desighed for. What i suggest is to goto the junk yard and pull a set of heads, put em on to get the car running. Take the old ones and have them ported and polished on the exhaust side with a LIGHT port on the intake side. Get a stage 2 cam for it and throw some 1.52 rockers on it. It will breath alot more and give ya about 35 to 45 extra HP....

David

Boham92RS

The 3.1 heads he found are from a 1990 z24 (fwd).. therefore they should be aluminum, and they should work? They already have a light port / polish job, and thats the main reason he wants to use them rather than pulling a set from a junkyard. I dont see why they wouldnt work.. as far as I know (at least in Camaros) they should be interchangable between the 2.8 and 3.1, I just dont know about the mounting brackets with the FWD Z24...

RenoLB8

1 year difference, both cars are z24's, and the body style didn't change then? It should be a direct bolt up. I say go for it. Only if that wasn't a generation change though. Let us know!

-Reno

KED85

YOU CANNOT USE THE RWD 2.8/3.1/3.4 HEADS ON A FWD VEHICLE.
They are DIFFERENT!
And will not interchange at all.
Honest.
When ya get to the head shop store, ask them to show you the two options. You'll see.
It's the intake systems and the vehicle requirements that dictate the design change!

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Chat Soon,
KED85
Karl
1985 Firebird 2.8 to 3.4 swap project for Smog Happy LA, CA

TomP

I've also heard that; that the installation of aluminum Gen II (FWD) heads on a Gen I (RWD) motor will cause the throttle body to point at the firewall. I can't verify it tho; I think everyone says (including me) that it can be done, but nobody's done it.


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!

KED85

The BIGGEST BUMMER is that you cannot make the Alum. Heads into the application for our F bodies.
You cannot!
The FWD valves are like on Big Block Chevy heads.
The F Bodies are like Small Block Chevy heads.
I had a pair in hand.
Both.
Saw.
Threw back.
Bummer!

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Chat Soon,
KED85
Karl
1985 Firebird 2.8 to 3.4 swap project for Smog Happy LA, CA

Red91Bird

Thats not true, you CAN use aluminum heads, BUT you have to change the pistons as well to aluminum head pistons. The pistons on the iron and aluminum have different pin heights. It can be done but for the little gain it is not worth it. As far as the big valves, most of the HO 3.1L came with the bigger valves if i am not mistaken. You also can buy after market GM heads with the bigger valves for the cars. Yes before i get flamed the 3.1L was considered a HO engine its marked by a LHO if i am remembering correctly. Forgive me i have been diving into ford and pontiac facts as of late. Anyways it will work just watch yer piston/valve/head clearances.

David

TomP

That's alright, the 2.8 is also designated H.O. That was in 1985, when it got Multiport Injection, a more powerful camshaft, and the same exact heads (valve size & everything) that the 3.1's had. The H.O. was dropped from 2.8 designation in 1986.


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!