Quote:

How does lack of sealant on a header bolt allow water into the tailpipe?

part of the bolt thread will grab the threads of the hole but there's still room for ~15psi of coolant to pressure thru. I use the OE shouldered studs w permatex #1 w headers and trim the outer fine threaded section so there's only enough threads left for a thin high grade nut to fit flush as any extra is a waste & contributes to the fitment prob

live every 24 hour block of time like it's your last day on earth