63 Mystery Motor...historical consideration

[Verne_Frantz]

rpoZ11,
That "Mystery Motor" only ever showed up in Nascar '63 Chevys. Bill France bent the rules again and allowed them to run, even though probably less than 10 engines were ever made. They were never installed in a production car. The engines were shipped to racers like Smokey Yunick, Red Fox and Junior Johnson. In '63 they were faster than anything on the track, but had terrible equipment failures with water pumps and the valve train. The last race of the '63 season was won by Red Fox with one.
The head design led directly to the MKIV "porcupine" type of valve arrangement and combustion chamber, but with different ports. The engine was known as the MKIIs ("s" for stroked because it used the '63 Z-11 crank bringing it to 427cid). The cylinder case used the pan rail and timing cover from the 409 (or Z-11). Although from the outside, it resembles a big block (MKIV), I don't know of anything else on the engine that will interchange with either the "W" or MKIV motor.
When the racing ban hit in Feb. '63, work on these engines stopped. Some extra parts were made and sent to the racers, then the pipeline ran dry.
At least one 2X4 intake has been found for this motor, which indicates there were plans for real production, at least for NHRA.
It's a great story...and a sad story at the same time........

Verne