The LS and the B20 are identical longblocks...Except for the B20's Larger Bore Size...Torque is what gets you moving and the Longer Stroke of the B20b/z & B18a/b, produces Plenty of Torque...Plus they are cheaper than a GSR, Same amount of parts available...Many GSR Parts are interchangeable with them...N/A motors only have Displacement as their largest power adder...There are Many Advantages to the Larger B-series motors...

Zee