I have converted my 1968 Cougar from manual drum brakes to power disc brakes, using all 1970 disc brake parts & components. When I got to the distribution block, I at first rebuilt the original core block from the parts car with WCCC's expensive "rebuild kit" with new o-rings. Very soon, the block started leaking from the brake switch, meaning that the brand new o-rings were not doing their job. Fail #1. That's when I decided to try one of these new repro blocks.
First attempt with repro block: as soon as I started to install the new distribution block on the fender apron, one of the mounting studs broke clean off with very minimal tightening. Fail #2. Returned to manufacturer in exchange for another one.
Second attempt with repro block: got the replacement and luckily the studs were sturdy this time and it mounted to the car without incident. Hooked up all the lines, bled the system, and did some braking trial runs in the driveway. Parked the car and... oh look, it's leaking. Fail #3. The problem ended up being simple, but should not happen... the copper washer under the brass nut / fitting on the top of the block had a manufacturing defect, giving it a slight crease in one spot, on both sides. Once I removed it and spent some time sanding down both sides of the washer to make it perfectly flat, and also sanding the slightly rough brass surface of the block where the washer goes (for good measure) and buttoning everything back up, the leak went away. Everything seems to be working properly now.
So, despite the frustrations and multiple fails, I still think this is a decent quality product that just needs a little more attention to detail / quality control. It's made from the proper materials and fits the car / brake lines just as it should. Functionally it seems to do its job fine, but I need to do more trial runs on the road before I can really be sure. As an alternative to a tired original, this'll do... especially when the rebuild kits for the originals aren't made properly. When you're talking about brakes and safety, I didn't really want to rely on 45-year-old o-rings, so it's nice to have something that's all-new.