as a beginner i have some questions please.
i just purchased a 59 short with the original automatic transmission. i know this is a rare option but it runs very rough and seems to have lost reverse (unless i am not finding the right spot?) keeping originality is not important to me and in my opinion the truck would much more fun if it were manual on the floor. i have some specific questions, hopefully you could advise me so i can make my decision.

1) does the original automatic trans. have any value to it?

2)if i found an original manual transmission should i be looking at only 58-59 or was the same trans used for many other years as well. will this be a exact part swap fit? or are modifications involved?

3)gearing??? if i swap with an original manual transmission can any simple gearing modifications be made so it will drive more highway friendly so it isn't screaming at 45 mph?

4)my ultimate goal is to have a 350/350 setup. but for now if i just swap out the trans. and retain the original engine can these be effectively mated? is swapping to a 350 trans. very difficult? any cutting or welding involved? or just bolt on brackets? i will most likely need the help of someone with experience so if i do not find an experienced stovebolter in my area is any good modern day mechanic capable of doing this or is it too specialized?
thank you for your help