The linkage part was one of the easiest things to do.
My 69 Camaro had a cable throttle cable (stock original) All you need to do is buy a universal cable from Lokar or other companies that make cable assembly's
They are Teflon lined, extra long, (so you cut to the proper length you need) install a metal stand off bracket, & route the cable any way you like.
All the bell cranks, pulleys, etc, usually is not needed.
MBHD