this is the one i put on my stock '70
https://www.summitracing.com/parts/hly-0-80555c
as with any holley carb install, new and rerouted fuel and vacuum lines were needed. once installed and filled with gas, it fired right up with the choke on high idle like it had been on there forever. never adjusted the choke, left it the way it came out of the box. after it warmed up, a small adjustment to the idle speed screw was all it needed. drove very good from idle to part to full throttle. went back and tweeked the idle mix screws, but that didn't make any significant change to the way it performed. could have left them alone. by the way, it didn't need a full 1" spacer to clear the pcv port. probably 3/8" would do it.