Briggs and Stratton 850 OHV Engine 1"
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 70mm from the side face of the engine and approx 105mm from the L/H mounting hole centre.