You're WAAAAAYYYY too tight. Torquing a bolt against a part that's able to compress is a lost cause, no matter what the manual says.

You can replace the gaskets now, or wait until they leak. When you do, tighten the bolt just enough to remove any slack, then tighten approximately 1/4 turn further. Wait a few hours and recheck the bolts. If any of them turn freely, go about another 1/8 turn tighter. This procedure has worked for me for a little over 50 years, with very few leaks or distorted gaskets and/or sheeet metal.
Jerry


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