hi guys i have a 4 mil 421 cub, clean up port from jeff, 39 pwk, +5 timing, shearers. though my electrical seems to check out, i was wondering if bad crank seals could be to blame for this? banshee has trouble cleaning out. If i dont rev 4th to the moon prior to shifting, it won't clean out in 5th. Even when i get th revs built up my guess would be it is in the 40 hp range. My brothers shee completly rips exact same setup everything. and jetting. My question is, should i tear down and check crank seals, and crank pressure?