Tru Power Engine Kit. 4-Cylinder Gas, 152 CID. 3-3/8 inch Standard Bore, 3-7/16 inch Overbore Supplied. Stepped-Head High Compression Piston, 5-5/16 inch Valve Length, Early Crank. Engine Overhaul Kit, Contains sleeves & sleeve seals, pistons, rings, pins & retainers, pin bushings, complete gasket set, crankshaft seals, intake & exhaust valves, springs, guides, valve keys, .020 inch rod bearings and main bearings. For H Series, HV Series, O4 Series (prior to S/N 33339), OS4 Series (prior to S/N 33339), W4 Series (prior to S/N 33339).