The early power steering gears (up until 1977) had input shafts that were 13/16 diameter. In 1977 the power gear shaft was changed to 3/4 diameter.
The manual gear input shafts were 3/4 diameter but had fewer splines than the power gear input shaft. So they will not interchange.
You can try Classic Industries in Huntington Beach, CA
Part number G5125 This is a 67-76 Camaro flexible coupling but I am quite sure that you could make it work.
Also you can try Ground Up
Part number ATE-8871 This also is a 67-69 Camaro flexible coupling.
The part may come to you with orange colored plastic spacers on the stop pins. Take them off and throw them away since your Chevelle has an intermediate steering shaft and does not need the spacers to align things.
Jim
The manual gear input shafts were 3/4 diameter but had fewer splines than the power gear input shaft. So they will not interchange.
You can try Classic Industries in Huntington Beach, CA
Part number G5125 This is a 67-76 Camaro flexible coupling but I am quite sure that you could make it work.
Also you can try Ground Up
Part number ATE-8871 This also is a 67-69 Camaro flexible coupling.
The part may come to you with orange colored plastic spacers on the stop pins. Take them off and throw them away since your Chevelle has an intermediate steering shaft and does not need the spacers to align things.
Jim