I have a 3.8 transmission T5 and a 1989 5.0 engine for my fox body. So what I’ve read the 3.8 bell housing and transmission will fit but I need a truck flywheel 11 inch. Proper balance of course. My question is what clutch and starter do I use?
3.8 bellhousing won't work. It will bolt up but the starter is in the wrong spot. The 3.8 transmission is longer so you need either a 95-95 bellhousing, or install an 86-93 bellhousing and change the input shaft and bearing retainer to the fox style.
Flywheel is a 10.5" flywheel 86-95 style. Get a clutch for that. Starter is any ole fox starter
The main difference between the two bellhousing is in fact starter clocking due to the difference in flywheel diameters. If you bolted in the 10.5" flywheel the starter won't contact the flywheel. The 3.8L flywheel is larger in diameter, so you could possibly use the truck flywheel and clutch but I've never actually seen or heard of someone doing this. Just much easier to use a 94-95 bellhousing and use standard Mustang parts (10.5" flywheel and clutch). If oyu want to try it, you need a 164 tooth, 50 oz flywheel. I personally haven't searched so I don't know what exists for these. I would assume you want a clutch kit for the flywheel you get, but unsure if th clutch disk spline count will match the t5 spline count as the f150 didn't used the t5 and had a few trans used.
One issue with the SN95 trans is the bellhousing is deeper pushing the trans back about 3/4" Might require some trimming to the trans tunnel to get it to fit.
I would recommend however that you try and keep the car as close to standard fox components as you can. You can convert that t-5 to fox input shaft length if you wanted. Just a recommendation of course.