can you downgrade from CV's too U joints?

[MaTTSuN]

i have a turbo 81 280zx but i wanna use the CVshafts for me 78. I have Ujoints from a 82-83 will they just blot on after i take the CV's out?

[blueovalz]

Good question. I know the turbo shafted cars used a 25 spline axle, matching the companion flange that slides onto it for use with the CV jointed shafts. Assuming Datsun used the same axle for the N/A and Turbo ZX cars, then the companion flanges would also swap as well. If this is the case, you should be able to swap to the U-jointed shafts. The companion flanges from one to the other will be the key. I would guess that if Nissan shows the same axle part number being used for both turbo and N/A ZXs, then they probably are all interchangable. Unfortunately, the Z axles had two differnent spline arrangements, which required different companion flanges even though the shafts were the same.

What always puzzled me is why Datsun went to a smaller spline axle (25 spline which is the same count as the 240Zs used) with the Turbo, compared to the previous N/A Z axles (27 spline which the 280Zs used).

 

I'm assuming you already know that the Turbo companion flange (25 spline) will not go onto the 280Z axle (but will fit a 240Z axle), and that you're using hybrid companion flanges (e.g. Modern Motorsports) made specifically for this swap?

[MaTTSuN]

thats what im intending on doing with the axles(putting them in my 78). if the u-joints dont match up i have the whole rear subframe of a N/A 2 put into the turbo chassis if the axles alone dont fit....im hoping i dont have 2 do that because thats allot more work, but i will if i have 2.