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TPI Tuned Port Injection discussion and questions. LB9 and L98 tech, porting, tuning, and bolt-on aftermarket products.

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Old 03-26-2006, 05:48 PM   #1
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Car: 82 IndyZd 88 IROC 84 Z28
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Corvette L98 heads

The search is down right now so here's my question

Is there any advantage of the corvette L98 heads over the cast version on my 88 5.7L?

I know with the aluminuim heads u can run more timing, better cooling and the weight savings are all a plus, but what about the compression ratio, valve lift etc.....?

What about the stock cams? Much different.

I was told these are the same heads as on the ZZ4 crate engines and they are rated at 355hp. What do I need to do to get that rating?

Looking for some good info on this comparison..Thanks
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Old 03-27-2006, 01:21 AM   #2
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I know that the stock L98 heads have the 64cc combustion chambers, and with the vette' heads 10088113 they are at 58cc combustion chambers, the compression ratio jumps quite a bit around the 10-10.4 range, just make sure the head hasn't been decked or warped. Got mine from ebay special $575 later. Not sure about valve lift, still lookin that up.

More info would be appreciated.
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Old 03-27-2006, 01:32 AM   #3
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the higher compression ratio will need more premium fuel usually. but 10-10.5 to 1 on aluminum is usually where u want to be anyway.... but combined with stock cam and 1.6 ratio rockers.. you'll see some good gains. they flow just abit better than the iron heads.

other than that i'd sooner go vortec heads and find a baseplate for them. vortecs new are same price as L98 vettes new, but they flow better. just need new manifold, thats all, which on tpi is abit more money.
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Old 03-27-2006, 10:23 AM   #4
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With the aluminum L98 heads, you also get screw-in rocker arm studs which will give you more freedom with cam/valve spring choices...
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Old 03-27-2006, 01:39 PM   #5
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No guideplates though...
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Old 03-27-2006, 02:43 PM   #6
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You can find good deals on them. I just sold my 87 Aluminium heads for 408 dollars, so the deals are there. If it was me I would go with 88 and up D port heads, big difference.
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Old 03-27-2006, 02:43 PM
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