GV4 (3.36) is the standard rear axle ratio for 308 manual on a Holden.

That is the correct tyre placard for a 10/75 onwards HJ XX7 or XU4 V8 van, so not a 100% positive identifier, but almost certain to be the original for the car.

If you still have trouble with photos email them to me and i'll post them up for you, holden@monaroparts.com. They are probably too big for the site, although I do have trouble with posting photos here on one of my PC's - there is an incompatibility problem with a version of Explorer.