Need Help 90 Cougar LS

I own a 90 Cougar LS. I have spun a bearing on cylinder 3 and am just going to buy a short block because this is not the first time this car has had this problem. The transmission is not in the best of shape and I pulled it also and am still deciding on a rebuild or does anyone know of a better tranny(like from a V6 mustang or T-Bird) that has better gear ratios and will drop right in there. Also does anyone know of some performance parts that will help the little 140hp motor a little bit because I am trying but no luck so far. :banghead:

Casey Harper