Engine conversion to GM for 1978 corniche - Rolls-Royce and Bentley Forums
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post #1 of 10 (permalink) Old 01-08-2020, 04:17 PM Thread Starter
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Engine conversion to GM for 1978 corniche

Please advise on the experience of Rolls Royce owners of the pros and cons of converting the engine to a new general motors engine.


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post #2 of 10 (permalink) Old 01-08-2020, 05:13 PM
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Its stupid. Period!

If you cannot run or rebuild the engine of your 78 Corniche, sell it and dont rape the car.

PCX 46761 (93 Turbo R)
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post #3 of 10 (permalink) Old 01-08-2020, 05:46 PM
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Agreed and you will seriously drop the value of the car, especially a Corniche.

1974 Silver Shadow
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post #4 of 10 (permalink) Old 01-08-2020, 06:25 PM
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Forget it. The RR engine is superb. There would be a secondary issue with powering up the hydraulics. Sell it to someone who will fix it.

1980 SWII LRL-41587C FInj
1976 SS LWB LRE-23114 Harkness RR
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post #5 of 10 (permalink) Old 01-08-2020, 07:39 PM
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There are no pros and only cons. You will seriously devalue your Corniche.
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post #6 of 10 (permalink) Old 01-08-2020, 07:59 PM
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By the time you go to all that work of fitting an engine that doesn't belong, it will be less expensive to deal with the RR engine.
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post #7 of 10 (permalink) Old 01-09-2020, 07:06 AM
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Look at this invoice :


113 k$ to install a brand new Chevy engine + transmission in a '67 Corniche !
A fellow member of the french forum just bought this car for.... 15 k€ ($ 16.700).
Fixing the RR engine would have been cheaper.
Market value of the car would have been higher.
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post #8 of 10 (permalink) Old 01-09-2020, 07:22 AM
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Apparently, you can LS swap anything. You'll probably need to carry over the hydroboost system from a truck for the brakes.

How about a powerstroke 7.3 diesel engine?
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post #9 of 10 (permalink) Old 01-09-2020, 01:41 PM
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Well my two cents...anyone who spends 113k on a Chevy engine conversion should be sent to an insane asylum.
Secondly, I would leave a corniche alone and rebuild the RR engine, properly maintained its bullet proof. If it were a silver spirit I'd say make it in to a hot rod, not a corniche, too valuable and too much future value potential.


1979 SSII
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post #10 of 10 (permalink) Old 01-17-2020, 02:22 AM Thread Starter
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Thanks for all the valuable advice.

I have spent $ 25,000 so far on essentially overhauling the car with new and rebuilt parts (found a very meticulous mechanic in Ashland, Oregon) I am hoping that I made the right decision since the resale value of this car is a maximum of $ 45,000

The following company could have replaced the Rolls engine with GM for $ 20,000:

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