15" wheel size for 60 Valiant
Looks real good. How difficult is it to find KH brake setups? Are they a direct fit? I will check out your build. I have had this car for a year and have been going over it quite a bit.
For the KH System;
You need everything between the control arms; but you get the 4" boltpattern on the discs, which, I have found to be more than adequate for street duty. At conversion time, I highly recommend to change over your braking system to a dual-system. It's not that hard, not complicated, not expensive, and infinitely safer.
I have run these systems on all my A-bodies since the 70s, and have always found them to be more than adequate for street duty.
There is a guy here on FABO, who often has reconditioned KH stuff for sale. I just can't remember his name right now.
If that fails, I have one very low mileage system left on the back burner. I took it off a crashed 68 Formula S many many decades ago.
If you're gonna do the brakes thing anyway, then
1) I would echo "33IMP" from post #8, and
2) "slant six" from post #2