One of the things i have learned works well with the big block pattern on the flanges is to add an upper and lower fastener between the two center exhaust ports. This spot was a constant troublesome area for leaks.I never used gaskets on the exhaust and had extremely minimal leakage after doing this. Look at the carbon trace on the head…
wonder if that would be a good idea for standard type headers, provided there is enough meat on the header flange to do so, and still allow reduced hex flange nuts to be used.
