Quote Originally Posted by David88vert
Actually, a 12a or 13b shortblock is a lot lighter than a V6 or V8. I've moved plenty of them around over the years.

The LS1/T56 is about the same weight as a 13Brew/tranny, and LIGHTER then a 20B/tranny.... the difference in the LS1 is about 30-90lbs depending on accessories still used. At 100lbs heavier thats still only a 3% increase in the cars total weight

The cast iron/AL head engines are around 150 lbs heaver (with a T56) and around 225-250 lbs heavier with an auto (though the rotary is heavier with an auto too, obviously).