master cylinder push rod

First time poster here. I'm resurrecting my 68 GTS after quite a few years of down time. During my initial build, I changed out the drums to power discs. Unfortunately that combo didn't work with a high lift cam. From what I've read the master cylinder I installed will still work for manual disc brakes, p/n 3580121 from a donor A-body. Looks like I need a simple 6 inch straight push rod with an eyelet on the end that mounts to the pedal bracket. Anybody have one or know the p/n? Thanks in advance. Steve