I used this plastic coupler item, found in the electrical dept. of a local hardware store. Had to grind down the flange of it just a bit so that it matched the OD of the seal, as I couldn't find a pipe or coupler that had the exact same OD as the seal. Can't recall if i needed to used a socket as well, to clear the entire length of the cam end...
I also did this with the engine out. So your clearance to drive the seal home will be more limited, if your engine is still in the car.
Red '91 164S and Black '91 164S