you would have to mount your transmission in the rear as the differential and transmission are mated in one assmebly (transaxle), you would definately have to fab out a cradle and run the differential tube to the rear from your LS engine. hasnt been done yet without a custom rear frame

Negative...Roadster Shop has a beautiful IRS setup for 1st gen's that you can buy as a rear clip or a full frame option and it doesn't use the torque tube and rear transaxle. Call them up, talk to Bryan and he'll explain everything to you and answer all of your questions.