And what about t56's that were in corvettes, cobra mustangs, and vipers?

 

IIRC... LS1 (98-02) T56's have a longer input shaft. You may need a custom bell housing. At least thats what I have read...

LT1 (93-97) T56's have a shorter input shaft and most people here use them. The 94 and up transmissions have a different first gear and are rated for more torque (Am I correct, fellas?)

Im not familiar with the other ones...

 

LT1 and LS1 T56's differ with the input shaft, mid plate and bell's, you can actually convert them vice versa. The gear box sells parts. i dont know about the others, im a GM guy.

 

oh and corvette 6 speeds use a trans tube, cant use in stock form and too expensive to convert. (unless you WANT to dish out the dough)

 

ok well I need a t56 for a 99 ls1 so I guess I'll just have to look for one off of a ls1

 

i think the 1993 t56 has a lower sixth speed gear than the rest.

 

You options are:

93-97 LT1 T56 (swap out bell, mid plate and input shaft)
98-02 LS1 T56
04-06 GTO MN12 6-speed (my recommendation, deeper gears, but pricey)
Vette LS1 6 speeds but the parts to swap out to convert make it not worth it.

I might be repeating myself up there but when i went looking, i had a hard time, my area was dry for T56's and so i opted for an MN12 at like double the price, and the month spent looking for one was frustrating.

 

Good post.

Just to the OP, be careful not to buy a 93 box; there's no LS1 length input with the right gear teeth, gear width and synchro compatibility to convert one to fit an LS1. 94-97 boxes are easy to change over.