I see supercars unlimited has 1970 o axle axles. I suppose the difference from the 69 is the outer bearing surface?
These are supposed to be 25% stronger than stock, anyone with any comments on these/this.

 

I think the answer to your question is yes.

The late ('70) axles have a different bearing and seal than the early ('67-'69) axles.
The '70 has the seal sandwiched between the open bearing and the retaining flange.
The '67-'69 has the seal pressed into the end of the axle tube and a sealed bearing pressed onto the shaft.

The axle housing tubes have different diameter and depth openings to match the different bearing/seal configurations.

 

I have the same axles,
Alloy 29.75
We can make you the 31 spline axles to replace the 28 spline also... A bit more expensive than the 28 spline but all depends on what your going to do. Jim

28 spline Alloy 145.00 (1967-1969) (will use the rw507cr bearing sealed and the seal pressed in the housing tube end)
28 spline Alloy 159.00 (1970 ) (will use the A9 oiled axle bearings and seal on the axle shaft)

28 or 31 spline stock and race axles (1967-1969) 370.00 pair
28 or 31 spline Stock and race axles (1970) 389.00 pair

Single axles available also BUT we prefer you get 2 if you are replacing stock axles.

Plus shipping of course.
Jim
JD