Transmission/Starter ID

Hey gang, I've been lurking on here for awhile and now I need some help ID'ing my Transmission and starter. It's a newb question for sure, but oh well. Hopefully someone one here can help me out.
My truck is a 1965 F-100 with a 352. I don't think it's the original engine that came with the truck, in fact I'm not sure about much with this one. It's been heavily modified and I bought it from a guy who bought it from the builder.
Bottom line is I need a new starter. I pulled the old one and bench tested it. I took it to the auto parts store, and they had no idea how to match it. They brought me the one that the computer showed for a 65 and it was a bit diffrent. It had the onboard solenoid, but it was of a different design and had a cover over it (heat shield maybe?) The mounting holes looked to be in the same spots, but neither one was threaded. My starter has the onboard solenoid, with no cover and the lower mounting hole is threaded. I could't find an id plate on it with a part number so there was no way to cross refrence.
As for the transmission, it's an automatic (3 speed I believe). I couldn't find an ID plate on it either.
What are some possible automatic trannys that could be put behind a 352? How can I figure out what it is, and what starter I need?
Anyone?

 

Really good question, but lack pictures of the engine and transmission. Without these I would just be guessing. Send pics, help will follow.

 

Could you take your original starter to a competent rebuilder and have it fixed? There's a good one here in Macon, and he guarantees his work. About the same cost as a parts store unit.