Why is my chevy 283 accelerator pump sticking?

i have a 1967 impala with a all fully original from factory 283 with power glide. i have the original Rochester 2GV and we rebuilt it... about a week after the rebuild i felt the pedal freeze.so i gave it a harder push and my car went kamikaze and took off like a toyota. i shut her down and rolled into a gas station where i disassembled the accelerator pump all together and i drove home. i had replaced the accelerator pump. when i first opened the carb up i saw the arm For the accelerator pump had been bent back and stuck. that explains why the pedal froze. and apparently when i hit it it stuck wide open. so i reassembled the pump for it to only happen again. i disassembled it and now im driving around without an accelerator pump. what could have possibly caused the arm to bend and keep me accelerating. is it the linkage put on wrong? please help.