hey i have a 86 sentra 1.6l. the engine just died on me and i was thinken about putin in a newer year engine and wanted to know if i would have to change the trans.

well, no, the bell housing is the same, as long as you use the 1.6

Sure? Cause the older ones use the E16i and the newer ones are the Ga16. I don't really know, just wondering.

i just found out that its a e16s and a b12 chassis. i found a SR20DE for around 500 i think i would need to change the trans. how much would that go for.

An Sr20 tranny is a good $300-$500. But you'll need to do a lot more than just change the tranny for an SR20 swap. Not so sure about the GA16 swap tho.