A Body axles 7 1/4 w/ 4 1/2 bolt circle

I have never seen axles like this with that bolt pattern in such a small rear end. The rear end in front of the one I took a picture of is also a 7 and 1/4 but has the small bolt pattern so I figured it has to be a rare deal if somebody wants to put 15 in Wheels without changing the rear end this would be the quick way to do it
you need the complete big bolt rear...the axles do not interchange