Auto tranny swap

[old fart]

I bought a transmission, transfer case and torque converter that I was told came out of a 1989 chevy 1/2 ton short bed pu. I got it to the house today and the driveshaft to the front end is on the drivers side. My 70 chevy SWB has the front driveshaft on the passenger side. Am I missing something here. I read posts on this forum about putting in a newer tranny with overdrive but I have not seen this problem posted. Is it possible the transfer case is wrong? How do I tell what tranny I have? 350,400,700r? Is there some way I can look at it and tell what it is? Can someone tell me how to identify the transfer case I have? Thanks for helping, Bill