looking at doing ls-1 swap. already have aftermarket tremec t-56 with the adapter plate to mount the trans to a t-5 bell. my question is this... are the input shafts the same length on the aftermarket and a 98-02 GM unit? or can i use this tranny with an ls-1??? any help would be greatly appreciated.

 

Tail lengths are differen't, you'll need a re-worked driveshaft.

 

the aftermarket T56 won't bolt up to a ls1 t-56 bellhousing. You would have to run a ls1 bellhousing, and the aftermarket t56 uses a T5 style clutch setup, not the ls1 type (hydraulic TO bearing)