THESE WILL FIT K0 THRU 82. THE C6HSA IS THE HOTTER OF THE TWO PLUGS. BOTH PLUS WILL WORK FINE IN THE 50'S AND 70'S Thread Size: 10mm Thread Pitch: 1.0mm Seat Type: Gasket Resistor: No Reach: 12.7mm (1/2") Hex Size: 5/8" (16mm) Terminal Type: Threaded Stud Overall Height: ISO Gap: .028" (0.7mm) NGKNUMBER: C6HSAC7HSA @ _ "SILVER DOLLAR TYPE" PLUG GAPPER TOOL SOLD EACH 1/22A (R2248)JUST A NEAT LITTLE TOOL !!!! GOES FROM .020" TO .100" AND FROM 0.6MM TO 2.4MM R2248