KH brake upgrade

I did this conversion on my convertible with 9" drums. The prop valve is a bit of an issue. Right now you will have a junction block/safety switch where the lines go from the master cylinder. The K-H factory setup had a separate adjustable prop valve downstream of this on the rear brake hard line. You can't buy this part, and it will be hard to find used. 73-up disc brake cars had a prop valve (of sorts) built into the junction block/safety switch (also called a combo switch). You can buy this from Classic Industries and others. The problem is that, being non-adjustable, it may still put too much pressure into the rear brakes. That was my experience (weight distribution and tires may be a factor). I resolved it by adding a Summit adjustable prop valve into the rear line. Some people put this between the MC and the junction block -- this is convenient for plumbing purposes, but I think it is a better idea to follow the factory practice and put it in the rear line coming out of the junction block. You can do this without cutting and flaring if you just buy a short hard brake line from the auto parts store (maybe 14-18 inches) and bend it into a loop. The output from the junction block goes into the input of the prop valve using this piece, then the output of the prop valve goes onto the existing rear line. This locates the prop valve directly beside the junction block -- you will find that the ones from Classic have a bracket on the side that is perfect for bolting them together. Tidy, mostly out of sight, and reachable for adjustment. If you have headers however this may not be practical. One more thing -- I bought new hard lines for the short ones that run between the MC and the junction block, because otherwise you may need an adapter for the end fittings -- the disc MC may have different sized outputs.