700R4 FAQ question

[67ChevyRedneck]

I was just reading the 700R4 FAQ section. I believe I have a 700R4 out of an '83 firebird. I was reading that '87 to newer trannys are better, which may be true cause my junkyard '83 700R4 blew. I also read that the spline on '84 to newer trannys is 30. It will be a few months before I can get a new tranny, so I don't want to pull the shaft to check. Is this true, and what is the spline count on 82-83 trannys? What I was thinking of doing was going to Advanced, don't laugh, I'm poor, and get one of their rebuilt 700R4 for $800. It also comes with a 15 month guarantee. I have yet to find anyone who will rebuild mine for less and give a 15 month guarantee. I was thinking of going in and asking for a tranny out of something like a 90 caprice to get the "better" tranny and give them my '83 as a core...they have no idea what is what. Will I need to change my input shaft??? When a tranny is rebuilt, will it even matter, or will all the components be the same no matter what year it "started as"? If so, I could just get another "83". Also, when I "ask" for a tranny, was there a vehicle they were better in? Ex: Camaro, truck, caprice etc..... Sorry for the length, but the FAQ concerned me.