A little help- Transmission Mechanics please...

[speednmark]

Ok so this is the second tiime ive had to send my baby off to the trranssmission shop in three weeks. This time i actually have no idea what caused the tranny to seize, but yees it froze on me. Its a 3 speed tranny. i think the munsie, anyways is it possible to take the core(guts) from a 3 or 4 speed transmission and install it using the same trannny casing that belongs to the origional 3 speed as of now(the three speed thats with thee truck right now- stock)?? if so what would i be looking at as of cost for the product, and does anyone have any suggestions as to where to go for such a thing- i live in austin texas, and by the way in case i get asked, its a 350 small block- stock....thanx - Mark taylor -