Pedal not returning all the way up?

[jlwdvm]

I am in the process of finishing up the install of a DSE booster and master cylinder on my 69 Firebird track car. I feel confident that the brakes are bled well all the way around. I am using a Wilwood proportioning valve in the system and as far as I can tell I have no leaks. The motor also makes plenty of vacuum for the booster. The problem I am having is that the pedal doesn't want to return all the way up after it is pressed down. Everything seemed to line up well when I bolted up the booster to the firewall. The clevis pin was a little hard to line up, but I got it through. Thoughts?