They should be 8x1.25mm thread. Early 1600s used 5/16".
If the nuts are original Nissan nuts, they'll be a 12mm wrench size. If they
were gotten from a hardware store or a nut 'n bolt place, they'll be a 13mm
I haven't ever tried to torque them, due to the practical impossibility of
getting a torque wrench in there, but I suspect I put about 15 lb/ft on
them. That's the same size thread as is used in a few other places on the
U20 engine, and they specify 13 lb/ft for those. See
Incidentally, 15 lb/ft is the same torque I use on the spark plugs. And
those I do torque.
> -----Original Message-----
> From: firstname.lastname@example.org
> [mailto:email@example.com]On Behalf Of roadster68
> Sent: Thursday, August 26, 2004 11:04 PM
> To: firstname.lastname@example.org
> Subject: Torque Specs for Exhaust/intake Manifold - 68 2000
> Looks to have the original studs and the nuts may be 5/16ths or metric
> equivalent. Can anyone help out on this? Larry.