It's the operating shaft that moves the pawl. The convertibles had a rather unique way of operating the OD due to the beefed up cross member being in the way. They used a rocker mechanism to function the pawl and it was mounted to a plate that is located under the transmission. It may be possible to use a good shaft from a convertible solenoid in one of the new solenoid bodies. The length of throw of the operating shaft is the only difference. Modifying the length of a regular short type may also be a choice.
This site has an illustration about the second or third illustration down the list.
https://www.fordmercassociation.com/...erchandise.htm