Originally Posted by rckchucker
False. An LM7 is not 40 lbs lighter than a 4.0. I just finished putting a 5.3 in my Jeep. I put a long block 4.0 on a scale and long block LM7 on a scale and the 5.3 was about 160 lbs heavier. My Jeep gained about 150 lbs on the nose. The only thing that changed was the engine. I retained my AX15 and 241 transfer case. I seriously doubt that an L33 aluminum block 5.3 is lighter than a 4.0 as well.
not sure how accurate these weights are as I've never weighed either the 4.0 in my jeep or the LS1 from my car but according to novak site for XJ (been considering the 5.3 or LS1 swap for my jeep down the road) these are the weights they listed
You'll be replacing one of three factory engines. Their nominal estimated, accessory loaded weights are:
•2.5L I4, 340 lbs.
•4.0L I6, 515 lbs.
Engines you may replace these with may include:
•Chevy Small Block V8 (Gen. I & II), 550 lbs.
•GM Small Block V8 (Gen. III), 525 lbs.
•GM Small Block V8 (LS1), 407 lbs.