Could be quite a task. Not to discourage you but over the years we have seen some issues. I am not sure that my first choice for a Hot Rod would be this combo. There are no aftermarket performance parts for this 250 hp engine. Trans design is not as efficient and some and also appears to have some limitations. Engine rod bearings are not "happy" at high RPM's and have been known to fail so regular "spirited driving" might have an impact.
Unsure as to exactly what has to be used however there are some things to consider. The Electronics of these cars are integrated to both the PCM (powertrain control module) and BCM (body control module) Starting and ignition is protected by a SKIM (sentry key immobilizer module) I do not know exactly what has to be present so more research would be needed. 02 and up engine & trans are incorporated into a single module (pre 02 had separate)
There was a guy that swapped a 3.5 into a Fiero : viewtopic.php?f=38&t=30992
There was an electrics guru that used to help us here, now spends time here :https://www.dodgeintrepid.net/
under the name of "peva" that may be more knowledgeable as to the electronics needed to do the job.
Please do let us know if you move forward with the project.
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