ARP MAINS NUT SET - COOPER S ONLY

Special "S" main bearings nut set (6).7/16"AF thread On all performance A series engines it is essential to ensure accurate and as near permanent location of the centre main bearing of the crankshaft as possible. Flexing allowed here, especially at sustained high RPM levels, can cause spun bearings, crank or main cap breakage with severe or mortal damage to the engine.