how do i get the ignition switch out of my 1977 chevy truck

my ignition key is stuck in the running position. most chevys this age range have a pinhole to release the spring and pull the ignition switch. this one doesnt. i have the ignition section of the colum (spelling?) out of the truck and dont see any release mechanism of any type, can you help? i can send more pics if that would help answer me. thanks