I'm going to be buying an Iron Duke Fiero here and my overarching goal is to do an engine swap with it. I havne't pinned down an engine yet (although I'm thinking about the 3800 or an LS) but I want to make horsepower in the ballpark of 300+ The Fiero I'll have has the 5 speed Isuzu trans right now and I'm trying to find transmission options that are capable of handling the horsepower figures I'm after.
From what I understand the Isuzu won't hold up, and the Getrag 5 speeds are hard to come buy and expensive.
That leaves some of the Muncie 4 speed transmissions, but I really want a 5 speed transmission in my car.
Are there any other transmissions that work in a Fiero? Or alternatively, is there a way I can beef up the Isuzu 5 speed so that it could handle the horsepower? I have a lot of fabrication tools at my disposal, but I have very limited knowledge about transmissions currently. With some help I could custom make parts that would be able to withstand the forces at play. I'm just hoping to get some awesome knowledge from you all to help me out.
I am looking into the f23 swap, it is the newest version of the 5 speed getrag (2000-2002 Cavalier) it is considered fairly bulletproof, all it needs is transmission mounts, something with the shifter mechanism and custom cables. Another is the f40, it's a 6 speed, needs custom cables, mounts, shifter mechanism, axles, etc.
The F23 is widely regarded to be about as sturdy as the 6 speed F40. It will also be considerably easier to swap, since it can use the stock Fiero manual axles - to include the ones that are plugged into your Isuzu. I've seen it bolted to any number of engines, including a number of LS4s and 3800s. I am looking at an LQ1 (DOHC 3.4) swap, bolted to an F23. Mounting brackets and shift cables will be the most difficult things to source. But both are available from West Coast Fiero, at a price.
If you want an F23, you will need the one from the 2.2 Cavalier, in order to obtain the GM Metric bellhousing pattern. It comes with 3.94 gears, so it'll work better (just my opinion) with an engine that has the capacity to rev. People are also building "hybrid" F23s that end up with 3.61(?) gears. I won't go into that here, as there's a good bit involved. Not a show-stopper by any means, though.
