Okay, so which is better? I know the 330hp 350 crate engine uses the vortecs and is only $2000. The zz4 uses the aluminum vette heads and makes 355hp. What if the cams were the same, what heads would make more hp?

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, Jon (91 RS too many mods to list), getting new engine in summer

 

The Vortec heads will flow more than the L98's so, everything else being equal, will make more power than the L98's. I wouldn't just draw the line right there and declare the Vortec head a better head though. The aluminum L98's have several things going for them...

1)They're aluminum, and aluminum is good.
2)They've got screw in studs opposed to pressed in on the Vortecs.
3)They use the old carbeurated intake bolt pattern (more intakes to choose from).
4)The springs will take more lift.

-Mark W.
'88 SC Camaro w/ 305 TBI

 

Now, the aluminum L98 heads are 58 cc, right?? I can strap those on a 305, right??

What is the casting # on the l98 aluminum heads??

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Godti
'89 Trans Am (Red)
305 TBI 5spd

[This message has been edited by Godti (edited January 30, 2001).]

 

Yeah, the L98s are 58cc and can be put on a 305. They also have the smaller 1.94"/1.50" valves so you don't have to worry about smacking your block with the valves.

KEEP IN MIND, the L98s don't have the EGR passages, so if you have to worry about emissions you are gonna have to find a way to pull the exhaust gas out of a header and route it to the EGR valve (just like the Vettes do).

Jason

[This message has been edited by 89BlwnRs (edited January 30, 2001).]

 

And if Im not worried about emmisions??

Are they pretty common to find?? Whats an average price?? What year engine would I pull them off of?? They are just in the Corvettes?? Or were they in the f-bodies?

[This message has been edited by Godti (edited January 30, 2001).]

 

the aluminum ones were only on vettes from around mid 80's to '91. There may have been a few put on camaros, but I doubt youll find an owner willing to part with them .

 

JP,

Look for '87-'91 Corvettes. Earlier ones had cast iron heads and later ones were LT-1's.

A ported and polished set of L-98's will work very well on a 305. Pay particular attention to the exhaust runners. They need to be opened up and fully polished.

BOR

 

If you can't find 'em used then you can get 'em new from www.sdpc2000.com for $799.

-Mark W.
'88 SC Camaro w/ 305 TBI

 

ther is a corvette c-5 sitting at a junk yard in my town. it burnt up but the motor is ok. don't know if those heads will work though, if interested email me.

 

If you're not worried about emissions it shouldn't be a big deal then. Your EGR system won't be operative so you might have to retard the timing since you'll be running a little hotter in the cylinder.

I don't know if this would set a code or not on with your computer, if you even have one, but I would guess a custom chip would be in order if you're gonna be switching heads and anything else. Just tell them that you won't be using your EGR system.

Only the Vettes had them, I don't know Vettes too well so I couldn't tell you what years.

I'd say go ahead and buy new GM Performance Parts L98 Aluminum assembled heads. They are just under $400 a piece and come assembled with valve springs that are good up to 0.500" lift and plus they come with screw-in studs which the Vortecs don't.

I'm pretty sure these heads require self-aligning rocker arms and aren't drilled for perimeter bolt valve covers, so you're gonna need some centerbolt vavle covers.

Hope this helped,

Jason

 

If you aren't running egr, and don't want to set a code, just put in a dummy solenoid, and run the egr wires to it. All the computer looks for is the electrical load of the egr solenoid. If it sees the solenoid, it doesn't light the ses, if it doesn't see the solenoid, it will turn on the ses light.

 

The problem with just hooking up the dummy EGR valve without changing the chip is this. The no EGR creats a hotter chamber and that = ping/knock at higher RPM. The computer controled distrib will advance thinking the EGR is working, the problem is the computer advances lets say from 30 to 31 and then the knock sensor detects ping so tells comp. to set timing down to 25 to get rid of ping. This is bad because it goes like this continualy and the detonation isn't good for an engine. That is why it's good to set the timing back but really much better to get a chip burned to not adjust timing so much or to not use EGR so to speak. How's that for homework :-) I haven't even swapped out my 305 TBI yet ;-)

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, Jon (91 RS too many mods to list), getting new engine in summer

 

No, the C5's have LS1 engines, which are completely different from the TPI heads we're talking about.

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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=-

 

L98 heads, where can I find them?

Thanks

 

You can find them used if you're lucky, or you can buy them new as ZZ4 heads from any GMPP dealer.