Tranny Code???

I was at the junkyard today and i found a b18a swapped rex. The tranny code was s1 or y1 which trannys are those? Should i get it(the tranny)? It looks like the swap was started but wiring and axles stopped them. Is that tranny geared shorter than my stock ls tranny? At that yard fwd trannys are $75.

If i am correct my tranny is the s1 ...damn i wish i could remember what that one at the junkyard was!!!

anyone?