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I’m getting ready to install the exhaust and intake manifolds. I have brass nuts which I assume will limit the amount of torque I can use to snug them down. Are there torque specs for the brass nuts and the tapered nuts?  Also the bolts that bolt the two manifolds together need to be replaced. Should I use stainless steel bolts or grade 8? Do I apply anti seize on the studs?



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The purpose of the brass nuts is so that they don't rust and bond themselves to the studs. This aids in their removal in the future. 

As Mark said, just get them all good and snug. Then come back after a few heat cycles and recheck them all. 


As for the bolts that hold the two pieces together, I would just use normal grade 5 bolts. Anti-seize could be used but I don't have much faith in it's efficacy over time, given the hot environment. When you are installing the manifolds leave these 4 bolts a little loose so that the manifolds can align themselves to the block. Once they are tightened to the block come back and tighten these 4 bolts.  

Edited by Merle Coggins
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I used ultra copper sealant on all manifold threads. I believe this kind of lubricates the threads, keeps from rusting fast, and helps keep any vibrations from loosening things up. It is also heat resistant and provides sealant for the block side to help prevent antifreeze leaks. I have been using it for my old tractor manifolds for years and the studs can still be reused after the manifolds burn out. JMO

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Thanks guys. I will the copper sealant and leave the 4 bolts loose until the manifolds are properly seated. Still will probably use grade 8 bolts because of the coating on them. 

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