Craig-
I believe the manual valve application in a race car calls for the valve to be placed in the cockpit within reach of the driver. That can be done either by placing the accumulator in the cockpit or by running a hose from the accumulator to a manual valve in the cockpit and then to the engine.
Incidentally, I ruined the cam and distributor gears in my stock 351W engine by pulling
oil away from the pickup while autocross racing. I rebuilt the engine with a Canton road race pan, but noticed the
oil pressure still dropped to about 20 PSI under heavy braking. I added the Accusump with electric valve and the
oil pressure hasn't been a problem since then.