I have a Super Tomahawk 5-8-2G/C chipper from approx 1983. with a Tecumseh 5hp engine Model H50-65484N Ser 4180D sold by W-W Grinder, (who is no longer in business). The crankshaft outside is 3/4", what I need is the correct end bolt size to hold clutch and pulley on the crankshaft, 5/16" 24 is...