Despite the block differences between Aussie and US 250's, I think you can use the L-code US 250 dipstick...PN 6750 should be the same. Maverick, Granada, Monarch, probably Versailles with 250 engine.
The crossflow one has a few extra bends in the pipe, but its similar to the 1971-1976 log head 250 asside. It's flimsier to get past the X=flow intake manifold though.