Printed in two separate parts, to be glued together. 

The main body can be printed with no supports if placed on the small angled back face as shown in the slicer screenshot. Supports optional for the head. 

The pins are press-fit into the engine mounting plate. It's quite snug on my engine, but I'm unsure what the tolerances are, so your experience may vary.

Printed with Polymaker Panchroma Marble Limestone PLA at 0.16 layer height and 15% infill.