Stuffing tube is 5/16 inch O.D. and runs into the strut, all the way to the back of the strut. Then from that end (prop end) goes in a bushing that is a short piece of brass tubing flared and with holes cross-drilled in it. This piece is 9/32 inch O.D. with 1/4 inch I.D.
Here is a short article on making the strut bushings (you can buy them from CC or other sources):
www.modelgasboats.com/Magazine...t_Bushings.html
At the engine end, you will need a collet on engine with round insert. Cut the cable to the correct length to have it bottom inside the collet and have about 3/8 inch free gap at strut end between drive dog and strut.
If any of this is unclear or you need more info just ask.