Grab everything you can. Its better to have left over parts then not enough. It also saves a few bucks over multiple trips to get the things you forgot. Deffinately need this stuff...
-Engine. Obviously.
-Trans. If going auto only, minus axels. Grab all wiring for it also.
-All accessories (AC, cruise, alternator, starter. Can leave power steering pump/tensioner.)
-PCM - make sure to grab PCM not BCM. PCM = 3 connector, BCM = 2 connector and looks just like a fiero ECM.
-Engine harness. From sensors to PCM.
-Oil cooler lines (grab an assortment from multiple cars if possible)
-Grab a tach wire connector from another vehicle with HEI ignition and a tach. Caddy's never had one so you have to look elsewhere. In a pinch a second coil power wire from a caddy will work after slight modification.
-Exhaust fittings. Manifold and expecially the center outlet pipe. These are hard to find aftermarket so grab the originals if possible.
-Misc vac line in good condition and extra wire loom. For the loom the factory GM stuff is much more heat resistant then aftermarket. Grab more then you think you need.
-Save all nuts and bolts. You'll need them.
-Engine mounting brackets. Rubber mounts not necissary unless you want to modify the cradle to use them.
(optional)
-Auto dim mirror + wiring. Its a good time to grab one if you want it. These Caddy's almost always have one.
-Interior/exterior temp sensors, delayed accessory relay, sun load sensor, factory power lock remote receiver, ect. Lots of little goodies in these cars.
-Deville strut tower brace. Works well for an engine TQ bar. It's 1" square stock with mounting brackets.
-Extra front valve cover ("V8 PFI" cast into it). Makes install slightly easier. Provides clearance for decklid hinge without needing to trim it.
92-93 4.9 Deville fuel pumps are the same part number as 88 2.8 fiero. 85-87 2.8 pumps also work fine. 94-95 caddy are different and wont fit without tank modification (not recommended but possible). If your converting from a duke you'll need a new pump. I wouldn't trust one from a wrecking yard but you can if you want.
If going manual attempt to find an Allante starter. It will make the install much easier and is a better starter in general.
[This message has been edited by Fieroseverywhere (edited 12-27-2010).]