Torque Question....

[Larry S.]

My 1966 bigblock (427-425HP) just had the Holley carb rebuilt, and I am reinstalling it and I just realized that I dont know how much to torque the 4 nuts/studs that hold the carb to the manifold. Also, the torquing procedure if any.
Any thoughts on this issue?
Thanks in advance.

[Chuck S.]

Re: Torque Question....

Holley mounting nut torque specs were 14-18 lbs-ft in 70...I expect the spec was the same in 66, but you can confirm by checking the carb installation page in the appropriate engine option section in the back of the 66 AIM.

Good torqueing practice is to torque in an "X" pattern in three increasing torque steps. At this low torque level, you may arrive in only one step if you're not careful...torqueing in steps is preferable, but it's probably not a big deal at low torque level.

[Jack H.]

Re: Torque Question....

Check your copy of the AIM. Sometimes they don't repeat the carb to intake torque specs from the base engine on optional engine carbs, but you should find the call-out as 14-18 ft-lbs.

The proceedure is to cross tighten opposite nuts and most start by bringing them up half way then making a second pass to get to the final torque spec. Don't be surprized that the absolute specs are rather low...you want the carb to 'ride' on the intake gasket allowing thermal expansion/contraction vs. 'squashing' the gasket flat/tight!