Tell me more about thermactor exhaust port bumps. This bump on the roof of the exhaust ports was to help mix air from air injection. Is this correct? I'm reading that this bump can be safely removed without causing water leaks or weakening the port walls. Is this correct?
My CJ heads with large valves and D shape combustion chambers, have this exhaust port bump, and the heads have an obvious place for an air injection hole to be drilled above and outside the exhaust port, though no holes were drilled.

 

yup i did this to my cleavland head, you shouldnt need to enlarge the ports, just grind the bumps down smooth with the rest of the runner, clean up, de bur, and smooth everything out nice and smooth all the way through, and they should flow nicely for you. good luck DW