Gas Pedal on Floor Studs

[1968 K20]

Hello, I have a new pedal but it will not push on or stay on the studs. I pulled the studs out and pushed them in on the workbench where I can see what it is doing. I pushed the studs into the pedal and in about 30 seconds it pushes the stud out on its own. It seem like the socket in the rubber pedal is not big enough.
Was wondering if there is a trick or a good brand of after market deluxe gas pedal that mount to the floor studs? I'm sure there is already a tread on this but I did not find anything. Any help is appreciated.