The Molnar crank I got from a member here was at a good price. I think it’s the same one you got. (3.79 with 2.1 rod journals, 360 main) I’m using the Chevy 6.125 “power adder” rods because of a 671 blower on top. I’m already aware of the custom piston cost for my application. Little over 2 grand for a set of blower pistons for my build. It is what it is.
I don't have the crank yet. I started my 3.79 parts collection with the NOS 5.9 bare block and the Chevy rods. The BRC pistons in the F/S section would work if the wrist pin was .927 but they are .984.
It looks like I could do custom piston like the BRC but just have them made with a .927 wrist pin instead of .984. I can use my 6.125 x .927 rods with the Chevy piston mentioned below.
If your custom pistons used a .927 piston pin you would be using the rod specs that mine are if I'm not mistaken. I was going to buy the crank you purchased but I was going through another big purchase at the time and my car funds had to rebuild.
I don’t have a current Diamond Piston catalog to cross reference CH from a chevy for use in a SB Mopar application. I’m assuming they simply change the milling process to relocate the valve reliefs for a small fee….