The History of the Mystery Motor
Your article on Tom McIntyre's Mystery motor (Horsepower, Nov. '06) brought fond memories. I was at Smokey's auction in 1989 when he bought this motor. A couple of points on this and the Mystery motor in general (I was a historian for the Tonawanda Engine plant back then).
1) The engine in question was bought complete for $30,000 (or so we were told). It was the last complete Mystery motor Smokey had.
2) That Corvette was more than just a Z06 owned by Mickey Thompson. In 1963, as part of Speed Week, Mickey Thompson raced the Corvette powered by a Mystery engine in a Modified class. This restoration, we were told in 1989, was the reason for the purchase of the engine. This Corvette could be one of the rarest ex-racing Corvettes out there!
3) The exhaust manifolds. Rare? You'd better believe it. GM paid $3,000 for a set to put on its Mystery display engine. I originally restored this engine for a Tonawanda display. Back then, the NASCAR engines had to run the factory exhaust manifolds. The design of the manifolds used on factory performance engines was advanced mainly because of this rule. The Mystery motors' exhaust manifolds were the most highly developed manifolds ever put on NASCAR engines.
4) The Mystery motor and the Z-11 motor were identical with the exception of the 90-degree head-bank angle. The short-blocks were the same; they used the same crank (3.650), same rods, same two-bolt mains, same oil pans, same timing covers, and same fuel pumps. I know, I had one of each apart on a workbench. And they both had the same bore/stroke, 4.310x3.650.
5) Put a Mystery motor intake next to a Mark IV intake and the only difference is one is slightly smaller than the other. Think of the Mystery motor as a 71/48-scale model of the Mark IV.
6) The cowl-induction air cleaner wasn't "relatively" new, it had never been seen before on a NASCAR (or NHRA in the case of the Z-11). Again, the cowl intake was a Chevrolet first.
7) In the genealogy of the Chevrolet big-block was the Mark I, which was the Z-11 heads with a two-piece intake put on the W block engine, the Mark II, which was the Mystery motor, the Mark III existed on paper only and was to come from GM's purchase of the old Packard big-block, then the Mark IV, and so on. -Fran Preve, GM Powertrain Tonawanda Engine Plant, retired.
Reader's Letter
Your editorial about driving old cars struck home with us ("Spending the Good Money," Dec. '05). Although, our car is worth a bit more than the CC/Rambler or Ford truck. We drive the wheels off our '62 Corvette. In addition to daily driving, annual trips are made that are several thousand miles long. To make these trips possible, many changes have been necessary. No more 12:1 compression motors, 4.11 gears, and wild cams, but 350s with 3.36 gears, A/C, and cruise control. We know the purists get upset, but while their rides are sitting in the garage with their tops up so they won't get wrinkled, we are out on the road. The thumbs-up we get are worth more than the loss of monetary value, and we associate each stone chip with the pure enjoyment of the trip. Yes, the top leaks in the heavy rain, yes, the A/C barely keeps up at 75 mph, and yes, we need overdrive. The car is never finished anyway, so why not just do it, whatever you are tooling around in? -Bill and Sally Bethea, Fort Meyers, FL