They are not the same, the steering arm and therefore the geometry are changed. They will interchange, but WHY? You can buy new 67+ style spindles...

V8 65-66 spindles are somewhat in demand too, I for one have been idly searching for some.

 

65/66 spindles are different from your 68's

67/68 spindles are the same for 6 or 8 cylinder,
just the brakes are different.

 

Not Quite.

65/66 and 67 V8 (drum or disc) are very similar - the same 4 bolt pattern to mount the backing plate or disc mount. 68 disc completely different - the 3 bolt pattern. 68 drum the same four bolt pattern as the earlier disc.

65/66 6 cylinder smaller than any of the above - 4 bolt pattern.

John Harvey