NZ gets all kinds of cars, I remember renting a beauty jp import not avail in Oz for $25 a day in 1993

Early alloy centre H190 models such as the Datsun 2000 Sports do not forget were Imperial thread bolts unlike later H190 models,That difference can trap people,They were also 25 spline axles unlike the steel centre H190 models which were with a few exceptions 30 spline axles.

The Works Diff's used in the Stanzas were another thing altogether being based on a home market Datsun 180B Panel van housing and centre,These were 27 spline axles.

Much the same applied to the IRS centres where the Works centres used in the 710 Violets were actually R190 Centres another Works Special with basically R180 size but R200 Strength and axle stub size.

My advice stick with easy to source later stuff,The exception is actually the 620 Ute assembly as the 30 spline axles were used with an alloy carrier.

The six stud axles are not an issue they use a nice preloadable tapered wheel bearing setup that is perefect for rear disk conversions as it can be adjusted so there is no axle float and no pad knockback.

Another very important aspect of these axles especially with the narrower 620 models is you machine the end removing the 5" pcd six stud setup and end up with a blank axle end that is perfectly suited to converting to either standard Nissan 4x114.3 pcd or even a later Silvia spec 5 stud to match a silvia type front end conversion.

This flexability of being able to add your own stud pattern in an axle that has seen no welding or required no shortening and resplining makes for a bulletproof setup.
I advised Vinnie Rigoli to go that way years back for a very sweet Mark 2 Escort he was fitting an RS500 Cosworth Sierra Engine to and it has proven utterly reliable behind that 500 HP engine so I think they are fine for most any intended use.

great information thank you for this it puts another light on the little info available for the H190 conversions!

Thanks for that info dude.
I just learned tonight from reading a workshop manual I tracked down that the 620 will be an alloy head already. And it may even be as low as 4.8:1!
My mate has picked up the 3.888 for me today. And I'll be picking that up weekend after next when I take the deathtrap 1200 up the the north island to a big car meet.
I wont be doing much to the ute til after I sell the 1200.

In Australia all 620's were 1500 motors and ran a 4.625 ratio centre.
720 Models depending on whether they were 4WD Diesel 4WD Petrol or 2WD ditto variants engine wise could be between 4.1 and 5.1 ratios but most in Australia were either 4.375 or 4.889

Mine is a J15 too. I'd expect it to be 4.6, But the book says that 4.8 was an option too. And SR20 is almost a bolt in conversion onto the J15 Xmember. Which I have ready and waiting when the time comes.