Originally Posted by AbaZ

A b18a and a B18b have identicle bottom ends, neither one is more powerful than the other. Both have the exact same pr4 pistons, same stroke, same rods same everything. The only thing that is different is on the 96+ B18b's use a different Part # Oil pump, mainly for the crank sensor pick up, but rumor has it, the 96+ b18b/B20b pumps will be adaqute for Vtec head swaps.

The difference in HP between the B18a/b's are all in the Intake manifold, camshafts & ecu. Both engines use the exact same head casting.

Jeff