This has a 1" x 3-5/32" shaft, 9 Amp alternator (to run the electric clutch), and a fuel pump. If you purchase and engine with less than a 9 Amp Alternator, you will need to reuse the stator, and regulator from your old engine. If you purchase an engine without a fuel pump, you would need to reuse the dipstick tube, vacuum & fuel lines, as well as the fuel pump from your original engine.