Its off of either a 87 or a 88 2.3 liter mustang. It wont work with a 5.0 liter. The input shaft pilot area is too small. 5.0 liters had a bigger pilot. Also they wont hold up to the power. They can hold around 240 of torque.
Well the tag could have been swapped (unlikely) or someone could have rebuilt it internally to V8 specs (highly unlikely)
Easiest way to tell is measure the input shaft.
2.3's measure 0.59"
5.0's measure 0.668"
You can run the 4-banger trans. It will bolt up just like a 5.0 trans as they are identical on the externals. You will need a different pilot bearing. Unsure which one, i beleive it's from some sort of Mazda pick-up truck from the 80's You'll have to do a search on stangnet as it's a common question.
Driving on it will be like having steep gears, so it will make your 3.55's feel like 4.10's. Just don't beat on it and it could last a bit. For free it will def help you get the car running
Alright, thanks....I dunno if I'm gonna mess with putting it in only to take it out not long from now...my car dynoed 320 tq at the wheels and I don't think I trust my luck