Are you using a B&B clutch?
If so then I had pretty much the same problem with a low end street replacement clutch that I bought for my 69 340 Dart last fall. When I put the pedal near the floor I heard a scrapping noise.
Everyone said the disc in backwards or not adjusted correctly. What it turn out to be was that the pressure plate height was set too low when assembled at the factory.
When I bolted the pressure plate to the fly wheel with the disc in place. The clutch fingers over traveled and were already too close the the disc springs in the static assembly. So now when you push the clutch pedal down enough to release the clutch the fingers ended up coming into contact with the disc springs.
I took back out out the pressure plate and measured the height of the plate off of the cover mounting pads and compared it to the height of the old pressure plate that I had. I found that there was quite a difference.