I don't currently own the 441, but it still lives next door.
HL Supply just developed and Pop Up piston for the 390 (since you can not delete the base gasket on a clamshell) if you are looking for some addl performance.
HL Supply just developed and Pop Up piston for the 390 (since you can not delete the base gasket on a clamshell) if you are looking for some addl performance.