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Dear Cadillac enthusiasts out there, I have a question. I currently have a 1985 Cadillac Eldorado with the HT 4100 motor in my Caddie that's locked up! I found a 350 Oldsmobile motor in a 1977 Cadillac Seville. I also understand the 350 Olds motor came stock in the 1979 Eldorado's that carry the same body style from 1979-85 in the Eldorado's.

Is it possible to put the 350 olds motor from the 77 Seville into my 85 Eldorado and make it work properly? First of all would it fit? and secondly, how on earth would I get the digital electronics like the digital speedometer and everything else to work and function properly with the 350 Olds motor?

Can someone out there tell me if this will work for me?

Thanks

Moderator note: Duplicate threads from different forums merged.

Dear Cadillac enthusiasts out there, I have a question. I currently have a 1985 Cadillac Eldorado with the HT 4100 motor in my Caddie that's locked up! I found a 350 Oldsmobile motor in a 1977 Cadillac Seville. I also understand the 350 Olds motor came stock in the 1979 Eldorado's that carry the same body style from 1979-85 in the Eldorado's.

Is it possible to put the 350 olds motor from the 77 Seville into my 85 Eldorado and make it work properly? First of all would it fit? and secondly, how on earth would I get the digital electronics like the digital speedometer and everything else to work and function properly with the 350 Olds motor?

Can someone out there tell me if this will work for me?

Thanks
 

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1991 Cadillac Brougham D'Elegance 5.7 Litre, 1994 DeVille
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Re: 1985 Cadillac Eldorado (FWD) engine swap

Too many differences in cars for this question to be in the RWD forum.

The base engine should work but you'd need any different parts that those 79 eldorados had vs the RWD seville. The electronics were also all different then what the RWD cars had. But chances are the speedometer just as a sensor at the transmission that would make it easy to adapt.
 

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Cadillac Catera
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Discussion Starter #3
Too many differences in cars for this question to be in the RWD forum.

The base engine should work but you'd need any different parts that those 79 eldorados had vs the RWD seville. The electronics were also all different then what the RWD cars had. But chances are the speedometer just as a sensor at the transmission that would make it easy to adapt.
So the 350 from the 77 Seville would work?

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So are you saying the 350 from the 77 Seville would work? Also, what about the bcm and ecm on my 85? I met a mechanic who said the motor would maybe work in his opinion, but none of my digital items would function cause there wont be anything to plug them into on the 350.
 

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Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
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19,851 Posts
Re: 1985 Cadillac Eldorado engine swap

So the 350 from the 77 Seville would work?

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So are you saying the 350 from the 77 Seville would work? Also, what about the bcm and ecm on my 85? I met a mechanic who said the motor would maybe work in his opinion, but none of my digital items would function cause there wont be anything to plug them into on the 350.
====================
unless you have UNIMAGINABLE AUTOMOTIVE SKILLS -
a shop FULL of equipment -
and LOTS of spare cash - forget the 350 -

it IS possible to use the 4.5 - a very good motor -
but it still takes some modifications -
 

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Discussion Starter #6
Here you go, all the info you will need to do this job right.

http://www.radar58.com/eldo/swap.html

If you have the tools & skill set you should be able to accomplish this swap with the above info.
Dear BigCadMan_1 thanks for the info... This is everything I need to complete the job just like you said. Thank's a million!!!
 
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