torque on intake manifold

[pw520a 19]

Hello, I am istalling a old aluminum offenhouser intake on my 69 390, My question is would the torque specs be the same as the original cast iron? Does anyone have the original torque values, it would be very much appreciated. thanks. Gary

[jholmes217 65]

I would use the torque setting from another aluminum manifold if they are different from the original settings. Less chance of cracking the aluminum that way.

[bigperm2 10]

You can use the factory torque spec. Torque on bolts is based on the bolt, not the material that is being clamped. If you reduce the torque, you may not compress and seal the intake gaskets correctly. AFIK, there is no difference in torque spec. for factory aluminum vs. iron (e.g. 1978 302 cast iron vs. 1992 302 EFI aluminum)

[pw520a 19]

Thanks for the response, now all i have to figure out is how to buy and hook the throtle linkage and bracket to an edelbrock 750 on a vintage offenhouser manifold. Thanks again Gary

[jholmes217 65]

You can use the factory torque spec. Torque on bolts is based on the bolt, not the material that is being clamped. If you reduce the torque, you may not compress and seal the intake gaskets correctly. AFIK, there is no difference in torque spec. for factory aluminum vs. iron (e.g. 1978 302 cast iron vs. 1992 302 EFI aluminum)

 

For the actual manifold bolts, I agree. However, when putting the thermostat housing on and some of the fittings (temperature gauge, vacuum ports, carburetor studs) where you are torquing into the aluminum, more care is needed. I've stripped out thermostat housing and carb holes before, and wasn't even wrenching that hard.

Edited February 16, 2011 by jholmes217

[69StangRestomod 11]

normally they're around 30 ft/lbs