550 Horizontal Crankshaft Engine 3/4
Distance between mounting hole centres (front to back) = 162mm
and left to right is 79.5mm. They are 8mm diameter holes.

Crankshaft centre is 106 mm from the bottom of the base.

The crankshaft extends to 61mm from the side face of the engine and approx 94.5mm from the L/H mounting hole centre.