quote:
Originally posted by jack deryke:
351-Cs take 14mm plugs with tapered seats & no gaskets, so torque in iron heads should only be 7-15 ft-lbs. If by chance you have heads that use gaskets, the torque with a new gasket goes up to 26-30 ft-lbs for 14mm plugs.
For aluminum heads like in a new Harley with a gasket, its 8-12 ft-lbs for 10mm, 10-18 ft-lbs for 12mm and 18-22 ft-lbs for 14mm. Can't remember what size plug a Harley takes. I know what size helicoils they take, though....
Thanks for the reply Jack. FYI: A 1997 Sporster uses a 12mm plug. I found a thread insert mfg. that makes a special progressive tap for their inserts that doesn't require drilling. Using their kit, a lot of axle grease, and cutting threads a 1/4 turn at a time, I was able to put an insert in the head without removing it. The mfg. is "Recoil". The kit with 10 inserts and the tap was $110...
Fast Eddie (#2100 The "Highway Star")
