Speaking to Kevin is bad since he always thinks of ways to get you into trouble.

My question is: What is the weight of the LSx engines used in the C5's (with all accessories) and what is the weight of the rear drivetrain (transmission, driveshafts and suspension pieces)?

Uh oh. :leaving:

LSs engines are about 120 lbs lighter than the old small block Chevy engines were. It's mostly due to the aluminum block, but there is also a nylon intake that helps. With everything on there, probably a little under 500 lbs. I'm just guessing though.

Edit:
One source I found says a LS1 weighs 490 lbs with the stock flywheel attached. So an automatic transmission version would be about 30 lbs less.

full weight of the engine with accessories im not sure about but 120lbs lighter for the engine itself than an iron SBC is about right. its 80lbs lighter than the LT1 basically.

ill guestimate on the C5 rearned peices as ive taken them out many times, but have never cared to weight them.

rear craddle which includes all suspension and half shafts except the shocks(3lbs maybe?) and upper a-arms. id say 120ish maybe 150. brakes not included either.

rearend is 55 lbs

trans is 150ish. its the same as the fbody if anyone knows that.

torque tube 60lbs. including the driveshaft inside.

hope this helps you some