Got in touch with Tod over at Engnbldr. He let me know that hole is threaded the same as the rest of them M10x1.25, and said the reason is for different manifold styles. I definitely had exhaust coming out of it...
Anyway I will probably toss in another Remflex since I still have a slight leak with the gasket I got at Napa. Should be cheaper than getting the flange trued by a shop. I like the lower torque setting and hopefully that will mitigate the stripped-thread syndrome these heads always seem to get.
