I have a Miata and a Tahoe. I tow with the Tahoe, but I have seen a lot of people towing with their Miata(on the Miata forum I read). I think you could find a hitch or have someone fabricate one for you. As long as you get the tongue weight right and don't do anything stupid, it should be ok for towing.
I would strongly recommend you find an MG newsgroup/forum and ask others of their towing knowledge. Find out what kind of weight limits they have run into.
Um Ranger <> MG.. isn't just 4cyl, it is suspension, gearing and the like. Yeah my 4cyl ranger could tow probably #2500...
My malibu was rated #1000, and I am betting the MG is rated #1000 too, but I wouldn't want to tray it.
As many have pointed out, it isn't the weight that is really the problem, it is the SIZE. The capri 14 will stick up about 2 feet higher than the MG, and provide massive wind resistance. Aerodynamic? As a brick maybe. Proper term is "hydrodynamic" from the bottom only. Again, not a good idea.
Just wanted to say you're a brave man! I had a good laugh when I saw your photo in the Capri forums. I owned a '72 Midget, same color too, (sold it while ago - mid '90's), but I still own the Capri 14.2, sailing on Saratoga Lake since '88. Great boat and fun car - best of luck with both!
BTW, did someone bow you trunk lid? Seemed a common occurrence with that locking lid support!
Sorry, I don't have a good picture of the mount for the motor on the boat. I made the mount myself with some aluminum and a tig welder. I didn't want an electric motor with the battery to deal with and a sure as heck didn't want an motor mounted right to the stern and interfering with the Traveler and making something else for lines to hang on.
I made a mount that uses an old short shaft motor(antique 1948). I usually just use it to get out from the dock and then once under sail, shut the gas off and let it run til it quits and then kick it up so it clears the water.
Its kicked up in this picture. It was about 6 years ago on July 4th (the flag) and somebody took this picture. Mount weighs about 3 pounds and the motor about 15 or so.
I was just downstairs looking at something else and grabbed the camera.
This is the mount I made and the old motor I used. The motor is old but simple and very faithful. It was made long before recoil starters, so I have to carry the starter rope with a knot in it in my life jacket pocket.
The mount has stick on rubber coating on the inside so it doesn't scratch the stern and I epoxied a small stainless steel plate on back for the rubber feet on the mount to rest on lower down. The mount keeps the motor out of the way and still handy if a storm comes up quickly.