72 C30 spindels conversion

[Mags]

Hi. I am new to this site and need some help. I have a 1972 C 30 dually dump . I have had it for over 22 years use it in my landscape business. I went to have it inspected last week and they told me I needed new brakes and rotors for front. Brakes not a problem but the rotors I can't find anywhere. First option is do any of you have or know where I can get a pair ? Second option is converting to newer spindels so I can use the heavier rotors, calipers. I have been told from a couple members that they think 73-87 spindels would work. Has anyone do this and is it a straight bolt up or do you have to change other things to make it work ? I really need some help because I need to use the truck on some upcoming landscaping jobs. Thank You very much. Bill