Thought I heard my name called...
I've never done a 3800. And I didn't even stay in a Holiday Inn, last night.
I've read a bunch about them, though. Even remembered some of it.
Charlie pretty much nailed it.
The story is that if you use a Fiero manual tranny, you will likely only need the mount that goes on the front (accessory side) of the engine, and a custom dog bone/alternator bracket. Stock mounts will fit, on the trans, but you probably want to go with something sturdier, since even stock 2.8s will shred our mounts, given enough time. If you retain the trans that came with the 3800 (which a lot of people recommend) you'll need custom mounts all around. It's quite do-able, either way.
You will need custom headers or a muffler/exhaust with tight bends that bolts to the stock manifold (which sort of points at the trunk, unfortunately.)
You will need a RWD 3800 flywheel that's been machined down to the correct thickness (.84 inch, I think, but please don't depend on my info. It's out there, elsewhere.) That will pretty much provide space for a stock clutch, which may or may not hold up.
There are lots of aftermarket choices out there. I won't make any suggestions, since I'm having issues with my "previously favorite" clutch option, just now. May be a non-issue or a big issue. I'm not sure yet.
You'll need to have a harness built, and probably have the 3800 PCM reprogrammed. Phonedawgs was doing harnesses, but appears to have screwed at least one person on Pennocks, so I wouldn't recommend him. Darth Fiero, aka Sinister Performance seems to have the best rep, in terms of programming.
If I remember correctly, all of the Series IIs were cable operated, and all of the Series IIIs were fly by wire. The series IIIs had something like 260 HP, compared to the Series IIs 240 (I think) mostly due to a different supercharger. People that want to run those with cable throttles have adapted Northstar throttle bodies, and used Series 2 PCMs.
Ideally, whatever you do, you want a 98 or later Series II PCM. They are reputed to be easier to program/modify.
The W-Body (Grand Prix, Regal, Monte Carlo etc.) engines require a bit less "cobbling" to get them into a Fiero. The Bonneville and Park Avenue require a different tensioner and oil filter adapter, where the W bodies don't.
If I was going to do a 3800, I would look for one from a Regal. Their target audience seems to baby them and have the dealer maintain them, as opposed to GPs and Monte Carlos, that tend to get beat on like rented mules.
Maybe too much info. And again... it's all "hear-say". I've never done one.
My next project will be a 3900, from a G6 or Impala, if I can sell my other project.
Edit - The first I've heard of "gotengines.com" was on another forum, this morning.
