help w/LP setup

[sonix-man]

Got a new spyder sonix. Upgrades for LP:

Bob Long Torpedo Reg
Maddman Rocket Valve
Polished internals
Drilled Vertical Adapter hole bigger
Crossfire Compressed Air Tank


I can't get the velocity up. My pressure is 375 with heavy main and weak valve. I am getting velocity readings of max 262, yuck!!! what can I do.