Sorry it took so long to respond, life got in the way...

There is vacume to the booster, as far as checking the rest, the car is sitting outside in a snow bank right now, the joys of running a business out of a 2 car garage. It will also be pretty hard to listen for a vacume noise under the dash, the car's exhaust dumps under the running boards and even with mufflers, it will be too loud to hear a vacume noise, unless its huge. I can tell you that when you lift your foot from the brake pedal, it takes a few seconds (like across an intersection) for the pedal to return to the top stop (and shut off the brake light switch). If you hook your foot under the pedal and lift, it feels like there is some resistance to it returning. I'm pretty sure the brake booster is junk. According to the web site I bought the brake assembly from the master is suppose to have a 1" bore. Frankly, I didn't measure it, but I will also be doing that. Another thought, the disc brake calipers are from a Chevy pickup, I'm wondering if they have a larger diamiter piston then the Corvette would have had. I also have no idea what size the rear wheel cylinde diamiter is, maybe everything is just sized wrong? (I've been reading a little) Life was sure a lot easier when I used to get all the stuff from the same car, stupid "kits" anyway.

I remeasured (as best I could) and the pedal from the pivoit to the center of the brake pad is 15" long and the arm that applies the pressure to the master is 3 1/2" long from the pivoit to the bolt hole center. If I figure it right, that would give me a pedal ratio of about 4,2 to 1? Wouldn't that require some extra foot presure to apply the brakes? I will be pulling the car into the garage in a week or so to get things ready for summer, so I will be pulling the pedal out to reinforce the firewall and will get a good measurement then. Until a few weeks ago I didn't know the firewall was flexing. My car still has the bolt in floor pans so there is little support at the bottom of the firewall. I plan on welding the top floor pan in instaed of having it bolt in and I think I can add a 1/8" x 1" strap standing at 90 degrees to the floor/firewall joint and still clear everthing. That should give me the stiffiness I will need.

I know its not a sign that things are right anymore, but all the brake hoses were put on the car new last spring when I put this mess together.

As I understand it, the porportationing valve also has the brake residual valve in it, if the guy sent me the wrong valve and I got one from disc/disc instead of disc/drum, could that be my whole problem with the rear brakes?

As you see, my mind is trying to cover too many variables. I have over $1000 in these brakes and I sure can not afford to do all that again!

At this point, I'm thinking I will reinforce the firewall, modify the pedal ratio to somewhere around 7 to 1, and trash the booster (its ugly anyway). I'm going to measure the bore diamiter of the master, the wheel cylinders and the brake calipers, and see how those look. I may also go to a junk yard and get a porportationing valve from a 5Th Ave and trash this one I have now. I do plan on doing one thing at a time, so I know and can let you know what the cause of the problem is.

I would still like your imput on where to begin. The firewall is a diffinate, the rest is speculation right now.
Thanks guys. Gene