The case is also different slightly, cosmetic l know but still look better
Iv had both side by side
Ratios will be different too. Mine are anyhow as Iv had the ratios changed
OK...so they are very slightly different...but then again, so is an 02C.
The fact remains, the casings, diffs, final drives and gears are interchangable...so there is no 'advantage' in going 02J.
I agree, the newer box will likely have less wear...but if rebuilt, it matters not a jot whether it's 02A or 02J...as long as you fit the right drive cups for the diff.
As for ratios...there are sooooooo many gearbox codes that it's simply silly to say an 02J is 'better' than a 02A.
The ratios need to be matched to the engine and proposed use of the car.
But buying a certain casing because it looks better?
Surely not Brad?

If you want scene points/eBay rare points, then a 02C is where it's at

I'd have at least gone 02j it's a newer box
Valid point...
But if building with a certain set of ratios and a certain diff, I'd have gone for the cheapest bare casing.