What diff oil for racing?

[jey@frame.com (Jeff Young)]

While the Ginetta G4 is still a long ways from being done, I'm planning on
taking it to the Palo Alto British Car Meet (in the transport).  I've got no
drive shaft yet, but since the rear wheels will be rolling around a bit, I
thought I should put oil in the diff.

Any reccommendations on type, brand, and weight?  It's a Spridget rear axle;
the car is a vintage racecar only: no street use.

This is going to the lotus list as well since the rear end is basically the
same as a 7.

-- Jeff.