Can anyone tell me if the 5 speed trans on a 2.5 4 cylinder in a1988 s-10 will bolt to a 4.3 Vortec V6 out of a 1999 extreme s-10?

No Different Bolt Pattern. You Will Need To Purchase A 4.3 Trans. The Good News Is The 4.3 Trans Will Also Bolt Up To A V8.

Will the Bell housing swap. I know where I can get a bell housing for the 4.3. I just don't know if it will bolt up to the trans I have

as he said, GET a 4.3L 5-Speed tranny.