I have the sacrebird setup on my '72. It works great and replacement parts are right off the shelf from anywhere. That was the deciding factor for me.

I didn't have any problems setting up the proportioning valve- I used a stock disc one with an aftermarket adjustable knob style after it. My 275/60-15 tires are harder to lock up than the stock skinnies anyway.

Be careful not to use too big of a m/c bore. I originally put my kit together with an aluminum mc a bit larger than 1" bore and got a fairly wooden pedal. I think my new mc (smaller) is around 1 1/32 or something. Works good but I'm a big dude.

The initial cost and the parts availability is what scared me off from wilwood, ssbc, etc. My 73 dart I converted to 5x4.5" big bolt single piston brakes and they work awesome too, but I didn't want big bolt on my 72 demon.

Good luck

Rdr