So much for inclinations...
I did some research on the notion of building a long-rod engine. Using a 250 crank and 250 style pistons, one would need a 7.4 inch rod. After perusing the various manufacturers catalogs, the longest rods available are apparently 7.1 inches.
The Santucci book indicates that one of the disadvantages of the 292 piston is the overall length from the pin to the ring package, which leads to instability. One possibility, which I haven't yet looked into would be to use 250 style pistons in the 292, which would provide the some displacement, but a somewhat longer rod.
(According to my Grandfather's 1917 engineering books, if a pistons overall length is longer than the bore, it should properly be labelled as a plunger, not a piston.)
Whether any or all of this speculation will provide any real benefit remains to be seen.
