Slant 6 Vibration

From the looks of it the manifolds need to come off anyways. I double up on the felpro gaskets for manifolds to head. some use remflex there which you need longer studs for so for now i avoid it.. I used a remflex for the one between the manifolds where the intake sits ontop of the exhaust, well worth it for no leaks.

I just pulled the factory block heater last winter for that reason, leaking coolant