you could drop in an ls1 engine into an lt1 body / frame ?????

 

Depends on how much you like modifying your frame! You can make any motor fit anywhere with enough work. Long story short, it's gonna take a grip of work to get one of mount/fit correctly. The problem arises that the LT1 is based on the origional Chevy small block, whereas the LS1 is a new, very different, block(different shape/mounting locations etc.).

 

Not to mention the computer, sensors, & wiring.