you can widen the port, up to 26mm (or else the ring will snag), but if you raise or lower it (lowering wont do anything since it'll always be behind the piston) you change the port timing and even a couple mm's can make a big difference (both good and bad). Do a search to see what other people have done with the exhaust port and pay attention to the pros and cons. BTW it ill be the same as the one speed E50