I have a stock js440/550 piston port. What is the max I can mill the head for 92octane? Also can I reuse the headgaskette?(suggestions on best headgaskette) Do I need or can I do anything to the mukunicarb? Also when it's time to rebuild is it worth putting a reedblock 550 in there on a well ported and polished stage?

My plans for this motor is a good pipe and maybe some light porting or any other suggestions?