What year is your car?
You're going to need...
Mounts.
Coolant hoses.
ECM and engine wiring harness.
Rear heater hoses.
Throttle cable.
Fuel pump.
At a minimum.
I'm doing this swap, right now. 88 Formula engine and cradle into an 88 base coupe.
If you can find an entire V-6 parts car of the same year, you'll be waayyyyy ahead of the game.
If you have an 84, it will require a lot of wiring fabrication, as the 84 was never designed to have a V-6. Quite a few changes were made to accommodate it.
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Raydar
From the Department of Redundancy Department.