ok i have a chevy dana 60 front that was DRW but i machined the hubs and was going to install new rotors on it. i went to the store and i told them what axle and they said $112 a rotor. i asked to see one i took the measurements and it was 12 3/4 diameter 3 inches deep from mounting surface to edge of rotor and the rotor was a little over 1 1/4 thick. went back home. i had recently bought rotors for my rear 60 and they were only 23 dollars a piece. i measured them and they were the same as the front. the ones for the back when i bought them i said it was a for a 79' k20 pickup. can i not just use the 23 dollar rotors? i can not find any differance in them, i searched the site and did not find anything conflusive. any help will be greatly appreciated, scott

You are likely being quoted an expensive price because you are telling the parts guy "dually". Rotors from a srw front 60 (chevy and dodge) are the same as a dually with the exception of the holes for the wheel studs. the dually rotors are drilled for 9/16" bolts to hold the rotor to the hub, whereas the srw units are drilled larger to accept the shoulder of a splined (knurled) wheel stud which presses thru the rotor into the wheel hub.
Search would have answered this question guaranteed.

well i got it all figured out now. the differnace was that the other rotors have to be for a heavy duty application since its over a 10,000 pound truck. the others were 3/4 ton. i used a venear calipier and they miked the same, even the stud holes were the same and knurled the same, so all in all they are the same rotors buy the cheap ones.

The 1-ton rotors are different than the k-20, from the d60 bible:

6) Chevy rotors are 1.5" thick, dodge rotors are 1.25" thick, but the calipers are identical

So you might need different pads to get it to work. BTW, I've looked for the k-30 rotors and they are around $40 each, so take that for what it's worth...