5.9 Main Cap Torque Specs FSM vs Larry Shepard?

[macdrew77]

So the 1998 FSM says 85 ft lbs for main caps, but Larry Shepards magnum engines book says 100 ft lbs. Which is correct?

 

[TT5.9mag]

I go to 85 if using factory bolts. But I use a good thread lube on them. Like ARP. Any time I use an upgraded fastener (like an ARP main stud or bolt) I use that manufacturer’s listed torque spec. I said all of that to say this, the “correct” torque is whatever was used when the line bore/hone was done.

 

[jos51700]

I go to 85 if using factory bolts. But I use a good thread lube on them. Like ARP. Any time I use an upgraded fastener (like an ARP main stud or bolt) I use that manufacturer’s listed torque spec. I said all of that to say this, the “correct” torque is whatever was used when the line bore/hone was done.

This.
I'd run ARP and whatever they suggested, if I had the money at the time.

 

[DMC_78]

Anyone do 100 foot pounds on factory bolts? I followed the Larry Sheppard book, and now kinda worried.

 

[Bewy]

Pontiac V8s use 1/2" bolts for the mains, 100 ft/lb is the factory rating.