How can I id my transmission

[gim_bob]

I keep saying I'm "fixing" to buy this truck, its a 74 step side with a 350, and a 4 speed. For the record, I am to meet up with the guy Mon. afternoon to draw up a contract so that i may pay it off, its only 2500, but i find myself in a down and out position to where i only make about 100-150 bucks a week. I know i can find some beater that will do the job of getting me from point a to point b for 1/4 the price, but this truck means a lot to me, well the style of truck any how... now that Ive gotten my self off target, I am curious as to how to identify the tranny that is in it, if I'm not mistaken, it came with a 3 speed, it now has a 4 on the floor. Its pattern is R-1-3       that's about the most info I have at the current point in time             2-4(or OD, not sure) 
I'd greatly appreciate any and all input. Thank you.

[zieg85]

If one of the previous owners had one installed it is anyones guess what it is.  Post up some pictures and we'll let you know what you have.  Most likely someone installed a car 4 speed in place of what used to be 3 speed on the column.  Could be a Muncie, or Saginaw.  If it is an overdrive it could be the rare New Process A-833.  If 1st gear is really low Muncie SM 465.

[gim_bob]

Ok, I'll get some pictures up asap

[Irish_Alley]

the sm465 setup is
L- 2- R
1- 3

[lifted80gmc]

 

[joesgarage71]

Car trannys are smaller than the SM465 which is a large cast iron unit with the shifter comming out the top. There is no mistaking the 465, car trannys will have the shifter bolted to the side in the rear. So sittin in the dr seat the 465 shifter will be in the middle of the hump and the small trans will have the shifter closer to the seat.

[Irish_Alley]

http://www.mackstrans.com/transID.html