Some 340 Questions

Ok, what I am taking so far from this is the 340 heads are pretty decent on their own.

As far as transmission goes, I haven't explored underneath that far yet(some personal stuff going on), but plan on getting underneath real soon. What should I look for on the tranny for identification? It's a 4 speed, and as far as I know, it's the original.

Rear end gears, not sure what's in it, but would like something nice and streetable, like mid 3's(3.53??)

FF