: 500ci swap into a 79 Eldo, do-able?

09-09-11, 03:58 AM
I have a chance to pick up a 71 Eldorado 500ci complete w/trans for a couple hundred. Im wondering how much work would it be to
plant it into a 79 Eldorado with the Olds 350? Is it a direct swap or is there way to much work involved, and if so, what?
looking for any info from someone who's put one in a small Eldo before. Thanks.

09-09-11, 06:41 PM
The 80-81 Eldo had the 368 engine, which is the same big block
as a 500. You need to get all the pieces from those models to do
an engine swap. You can even change to a 76 500 ECU and keep the
79 Eldo fuel injection. Might need slight tuning, I can advise on this.

A far simpler swap is an Olds 403 small block into the 79. Just
use a 425 ECU, or I'll help tune the stock ECU. With a 2.73 axle
change and a free flowing exhaust, this will burn plenty of rubber.
I used a 76/77 iron intake manifold with the larger throttle body.
One problem was the oil filter.

Don't expect a lot of life from the TH325 trans driven by a 500
engine. If you plan to swap in the TH425 trans & final drive, you
have a major project ahead. Moving things for clearance, half
shaft adapters, custom parts everywhere. But you can get the
advantage of switch pitch and use a POWER DRIVE 65:57 chain
set to get a more economical 2.40 overall final ratio. And it
won't break with the big engine. That is what is in my 79 Eldo
and a 403. See pictures on sub albums of my PHOTOBUCKET.


(that is a lower case "L"71, not an upper case "i"71)

click on a Sub-Album
click on a picture to enlarge + explanation

Bruce Roe CLC # 14630

815 234-8039