Just another idea I had, is the cutoff seal necessary? I understand it helps seal combustion where it needs to be, but could it be removed in favor of a bigger port? For example, enlarging the exhaust port inward past the cutoff seal to allow more exhaust to hopefully get out. If possible, the exhaust port area could be increased by a decent bit.

 

That ring does a large part in keeping the flame front off the oil seals. It is critical to the longevity of a side port exhaust engine.

 

Do you think there's any potential for this no cutoff seal idea? Not sure how much larger the port could become but perhaps if the power gain was enough it would prove that there's more potential in the motor. I could see how it would affect the oil seals so perhaps something like that would be for an all out race application with frequent rebuilds. Around 220WHP is the cap n/a from what I've read, the exhaust just needs work. If a cutoff seal is needed, maybe a thinner cutoff seal could be used to allow a little bit more room for porting. Might be too much work though.