Internal and External? Parts swap, info please!

 

LS1 and LM7 or 5.7 and 5.3 are both gen III small blocks which makes them based on the same engine platform. a 5.3 uses a different block, pistons, piston rings, intake manifold, and exhaust manifold. internally they are interchangable all through except pistons and rings for the most part. the bore on the 5.3 is much smaller. the cylinder heads on a 5.3 also use smaller combustion chambers and smaller intake valve.

 

They also use the same cam as F-body LS1 engines from 2000-up. Different intake. Also, I think the ports on the heads are very close if not the same in size.

 

Coo thanks guys!