Looking for a 1970's chevy rear dually axle. I need it for a trailer. I am looking for a center bolt to center bolt spacing of 40.25". I have found that this axle has the spacing. Are these a hard axle to find? I found one at a junk yard without the ring gear, carrier, etc.

Does anyone know what a 1970's rear dually axle would be? D60? 14 bolt? ???