I went to put on my aluminum drive shaft on my 97 lt1 and the u-joint was bigger and would not go into the lt1 yolk. I take the ls1 has a bigger yolk, and if so if anybody has on they want to sell let me know, if thats not the case I guess i will have to come up with something else.

 

that doesn't sound right, I had a DS on my 97 LT1 6spd and when I got my 99 LS1 A4 I pulled the DS right off the LT1 and on to the LS1.......though I did have a moser 12blt, im thinking the length is the same. As far as the u-joint, I can't be certain. TTT for you.

 

I'm thinking the DS might have the wrong u-joint into it; probably an adapter U-Joint for hooking it to a 12-Bolt or similar. Replace it with a stock U-joint and I'll be it'll fit fine.