Swapping a Tecumseh for a Cobra

[amatureleccy]

This question, isnt just about swapping engines, but about swapping an engine that drives a rear cylinder (by cylinder, I mean roller) with and engine that drives normal wheels. 

I have a Hayter mower with a rear cylinder drive.  The engine is a Tecumseh BVS 153 ES.  The rear cylinder is connected to the motor via pulley that protrudes horizontally from the side of the engine which drives a belt that is connected to the side of the cylinder.  This is different from a wheeled mower where a pulley on the vertical blade axle drives a belt that is connected to a pulley on the gears box on the rear axle.

I have a spare motor with the latter arrangement. 

QUESTION = Are they nterchangeable.

Thanks all for sharing any thoughts.