I read somewhere that when doing a T5 swap you can use your original starter if swaping from an auto. Since I have the FMX 3 speed auto, does this mean I can use my original starter? Thanks!
The FMX starter should interchange. Ford pretty much used the same starters for lots of applications. Stay with a starter recommended for you engine type and you should be OK for the most part. My friend replaced the FMX in his 69 Mach with a C4 and used the original starter.
Not from my findings. My car started life as a 6cyl 3 spd T code. When I put in a 289 backed by a T5, I re-used the original 6 cylinder starter motor. This was with a 157 tooth 28oz C6ZE flywheel. Later, the 289 was replaced with a 5.0HO fitted with a 157 tooth F1ZE 50oz flywheel. Same starter. Still no issues. This is using the '91 bellhousing behind both the 289 and 302.
EDIT: I just did a search on Autozone for a '65 with both 6 and 8 cylinder engines. There are different part numbers listed for each application and different again from auto to manual (again for each). But, in my case, it's worked so far.