This will be my third DT header and this is the first one that has not completely sealed for me. But, I did mess up the gasket a bit and I only torqued to 20 or 25 ft/lbs so I am not surprised, I have no reason to think it's the flange. With the Remflex is was completely sealed. Of course, that is part of their thing, the gasket is supposed to compress to half it's starting thickness to make up for warped flanges. I wonder how they hold up over time?
As for bolts into the head, that cannot be good. I do not want all that twisting force going onto an aluminum thread. Looking up a recommended m10 torque rating into aluminum I found 19 ft/lbs recommended. But, with using a stud that twisting force all happens at the stud/nut interface so we can go higher.
Since Remflex says to go to 20 that is what I will do.
Another issue would perhaps be corrosion caused by aluminum and steel simply contacting each other. I notice the OEM Toyota studs I ordered have the head side fully dipped in red stuff (assume loctite or similar.) Perhaps they put so much on to keep aluminum/steel contact to a minimum.
