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91 Fifth Ave Engine Swap

2409 Views 3 Replies 4 Participants Last post by  mydodgedip
I have a 91 Fifth Ave with 3.3l (victim of the dreaded valve train pedestal break) and 4speed auto and would like to know if the 3.8l is a direct swap or would I need to swap out the computer also. I know the engines are identical externally so I know it will bolt in, but if I have a difficult time finding a good 3.3 I would like to upgrade for as little as possible. This car is going to be dead stock so I don't need anymore power than either of these engines provide...Also would like to know what years I can use for this swap. Thanks to all that reply........Goonior

05 Magnum RT
07 Sebring
91Fifth Avenue
79 Cordoba
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· What sanity?
495 Posts
You do need a 1991 3.8 ECM to go with the 3.8 engine. Not sure just how new you can go with the engine, but you need the actual 1991 ECM for sure. It will be hard to find at the yards... the 3.8 was optional that year on only the Fifth and Imperial.

· Fleet Owner
182 Posts
The transmission gearing was different 3.3 to 3.8 as well, right? Might be a setting in the TCM to change.
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