Anyone know what check valve I need when converting rear drums to disc?

 

You need about a 2 psi residual valve for discs.....drums can typically have as high as 10 psi. FWIW, the drum residual valve can work with discs - you might just notice slightly lower rear pad life. I would say go ahead and do the swap....if you are not happy with the residual pressure, then change it. I have been involved with many rear disc swaps and only a couple of master cylinders had rear residual pressures that were noticeably too high which caused abnormally lower rear pad life but never had any other adverse effects. All of the 1 ton sized brakes did not appear to have any issues with the residual pressure - the only issues I can recall were with half ton sized brakes and master cylinders when swapping to discs - I'm not sure why.

 

I found my brackets, so now I'm going to get the Chebby calipers and stuff.
Thanks for the input on the pressures.