Exhaust port porting?

Porting the exhaust properly should help a great deal. Here is an example from a RPM head we just did for a 505. First, out of the box flows and second ported. These were using a 2" pipe. In tests we have seen RPM exhaust ports go over 300cfm.

Lift............OOTB.............Ported

.100............57.................58
.200..........112................125
.300..........163................182
.400..........197................217
.500..........217................240
.600..........231................257
.700..........239................285

If yours are unported you could see a similar increase.