pw520a 19 Report post Posted February 14, 2011 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 Quote Share this post Link to post Share on other sites
jholmes217 65 Report post Posted February 14, 2011 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. Quote Share this post Link to post Share on other sites
bigperm2 10 Report post Posted February 14, 2011 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) Quote Share this post Link to post Share on other sites
pw520a 19 Report post Posted February 14, 2011 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 Quote Share this post Link to post Share on other sites
jholmes217 65 Report post Posted February 15, 2011 (edited) 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 Quote Share this post Link to post Share on other sites
69StangRestomod 11 Report post Posted February 15, 2011 normally they're around 30 ft/lbs Quote Share this post Link to post Share on other sites