Fox mustangs are from 78 to 93 I believe. These were the first real mustangs after
the mustang II (pinto) fiasco. Theres tons on the road and in the JY.

 

So the FOX mustang is the 79 to 93 generation mustang?
Also due to the 79 strut tube being longer than the later generation rx7's I'll still have to use a spacer, but if I switch to a later first generation rx7 strut tube that problem should be solved correct?

 

Only the rear shock interchange between the Mustang and the RX7. The only variance from 79-93 was the SVO but I think that is just a parts number hickup as those cars came from the factory with adjustable Koni's. I owned an 85 SVO and an 85 GT at the same time and there was no difference in the physical size of the shock. 94-04 Mustangs have the same rear suspension as the 79-93 but the shocks are longer.

The front strut on a mustang is completely different than what you have on an FB RX7. There is no interchange here.

Mustang DA Yellow Konis work really well. In fact this year's June Sprints EP winner (81 FB 13B) is running them.......or at least that is what was on the car when he bought it.