Anyone Using a Small Block Gear Drive?

Any thoughts on this as an alternative to the milodon gear drive?
SMALL BLOCK CHRYSLER 273-318-340-360 V8 GEAR DRIVE. | eBay
Haven’t seen that one before, looks like you don’t have to drill the block for it? Already have the Milodon or would put way more consideration into it. Do you know anyone down your way running one of the units you posted? Good, bad, indifferent experiences?