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Does Anyone Know Anything About the 1985 Corvette L98 Heads?

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Old Dec 5, 2023 | 03:37 PM
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Does Anyone Know Anything About the 1985 Corvette L98 Heads?

How different are they from 1986 Camaro LB9 heads? I know they are both 58cc. I ask because I own an LB9 car but I can get a set of '85 Corvette heads for free.
Might be good just to practice and learn head porting on. Is there any real difference? I know 87 and later L98s were Aluminum.
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Old Dec 5, 2023 | 05:08 PM
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Re: Does Anyone Know Anything About the 1985 Corvette L98 Heads?

Originally Posted by Vinscully50
How different are they from 1986 Camaro LB9 heads? I know they are both 58cc. I ask because I own an LB9 car but I can get a set of '85 Corvette heads for free.
Might be good just to practice and learn head porting on. Is there any real difference? I know 87 and later L98s were Aluminum.
From Mortec
462624.....75-86...350/400......76cc chamber, 1.72/1.5, 1.94/1.5 or 2.02/1.6 valves
I'll guess 1.94/1.5 IN/EX for a 350?
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Old Dec 5, 2023 | 05:51 PM
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Re: Does Anyone Know Anything About the 1985 Corvette L98 Heads?

Originally Posted by Dyno Don
From Mortec
462624.....75-86...350/400......76cc chamber, 1.72/1.5, 1.94/1.5 or 2.02/1.6 valves
I'll guess 1.94/1.5 IN/EX for a 350?
From reading the Corvette forums, the L98 heads for 85 and 86 are different than the standard 350 heads from 75-86. I know they have 58cc chambers but so do the LB9 heads. I was wondering if anyone knows if they are the same as LB9 heads or different.
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Old Dec 6, 2023 | 07:01 AM
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Re: Does Anyone Know Anything About the 1985 Corvette L98 Heads?

Mid 86 the Corvettes got the 58cc L98 heads. 85s had 76cc like DynoDon told you. Ive heard of people using the 58cc aluminum L98 heads on 305s but there are big differnces in them and the LB9 heads. Valve size and etc..
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Old Dec 6, 2023 | 09:52 AM
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Re: Does Anyone Know Anything About the 1985 Corvette L98 Heads?

The larger bore of the L98 might allow for larger valves, and that could lead to clearance problems with the small bore of the 305. Even without actual mechanical interference, the shrouding could restrict flows. You'll determine that once you flip the heads and start measuring. It sounds like the '85 heads are not a good starting point, but getting the casting numbers would be critical to verify that.
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Old Dec 6, 2023 | 01:13 PM
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Re: Does Anyone Know Anything About the 1985 Corvette L98 Heads?

Originally Posted by Vader
The larger bore of the L98 might allow for larger valves, and that could lead to clearance problems with the small bore of the 305. Even without actual mechanical interference, the shrouding could restrict flows. Youy'll determine that once you flip the heads and start measuring. It sounds like the '85 heads are not a good starting point, but getting the casting numbers would be critical to verify that.
if it is a stock 1985 early 1986 Corvette it has 1.94/1.50 valve, crack prone 76 cc 624 heads on it.
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