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L98 differences?

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Old Aug 27, 2017 | 07:58 PM
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Default L98 differences?

I have a 1991 L98 coupe and Have always wanted more power. I found a 1987 donor L98 motor that was completely rebuilt with high performance heads, cam, lifters etc. the engine is also including a 700 R transmission. Is this combo compatible with my car? If not, what else can I fit in my car or should I just have mine rebuilt?

thank you
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Old Aug 27, 2017 | 08:19 PM
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Without knowing exactly what they did, its hard to say what caveats are here. It'll fit and is compatible.

If its a performance engine then your chip must be retuned to run this motor before it will really run well.
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Old Aug 27, 2017 | 09:54 PM
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I have a chip from Alvin at PCM of NC. I'm sure he can program it for me. This is all I know about the motor I'm looking to buy:

the bore was 4.030, valves I 1.940 and e 1.500. Combustion chamber is 76 ccs. They used a comp cam with tons of specs. Valve timing also has a bunch of specs They used pro magnum 3/8 inch rockers. 9.0 : 1 ratio.
The information shows a ton of other specs.

Do your think this rebuilt L98, auto 700R trans, larger radiator and beefeater rear end. Plus the 1987 Donor car is worth $3000? The fiberglass is all good the interior is rough
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Old Aug 27, 2017 | 10:42 PM
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your 91 heads are probably better re-evaluate before dropping it in as is
more compression and better cyl head flow helps
if you pull the valve cover off youll see a part # stamped on it. What are the last 3 digits?
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Old Aug 28, 2017 | 06:49 PM
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NOPE!

http://www.ebay.com/itm/BluePrint-Sm...-/131493818156
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Old Aug 28, 2017 | 08:22 PM
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Originally Posted by pologreen1
Will my top end from the L98 fit on this engine pologreen1? Or do I have to convert to carb?
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Old Aug 28, 2017 | 11:21 PM
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It would, but you'd be WAY further ahead buying a converted lt1 intake or miniram, even superram if you can find one.

I like carb though too.
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Old Aug 29, 2017 | 12:01 AM
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Originally Posted by pologreen1
It would, but you'd be WAY further ahead buying a converted lt1 intake or miniram, even superram if you can find one.
TPIS for a miniram. The superram is out of production so finding one is not easy. There was a NIB on fleabay a ways back that fetched north of $1000.

Which ever way you wish to go there's lots of info here to read.
Including lots of lessons learned. So you don't have to make your own.

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