I have maintained for a number a years that you could park a Model T at any large Mall in the country, and leave it unlocked, and have every confidence that it would be there when you returned. There would be a crowd of people, but not 1 in 1000 could get in, start it, and drive away.
Yet, beneath all that antiquity lies the very heart of the modern automatic transmission--the planetary gear set. Compression ratio of about 4 to 1, it will run on almost any grade of anything that might remotely be called fuel.
For some reason, Henry Ford believed that the crankshaft needed to be flexible to some extent. maybe due to manufacturing tolerance on the early cast blocks. Anyway, that imposes some limits on rpm. The T is happiest below 40-45 mph, and the more robust A under 55-60. However, if equipped with a balanced, and otherwise improved original engine, you might be surprised at the speeds the T can obtain. Of course with only 2 wheel braking, you'd be a fool to go very fast.

One thing to remember in the odd case you find yourself careening down the road in a Model T--pressing any two of the pedals will slow the vehicle--you would either engage low speed, the brake, or a dab of reverse==but since the gears are always meshing, and shifting is done thru brake bands and clutches, there is no gear clash, or damage.

I am still hoping to find a Model T who owner will let me crank start it. I know to keep my thumb along side the handle; not wrapped around it!

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1982 300SD " Wotan" ..On the road as of Jan 8, 2007 with Historic Tags