Briggs and Stratton 6HP OHV Intek Engine Threaded Shaft
Distance between mounting hole centres (front to back) = 160mm
and left to right is 78mm. They are 8mm diameter holes.

Crankshaft centre is 105.9mm from the bottom of the base.

The crankshaft extends to 61.8mm from the side face of the engine and approx 97mm from the L/H mounting hole centre.