I agree. 6500 revs on a 216 seems highly unlikely, and I am not sure what it would be worth. Bill Fisher's dyno tests with the wildest cams and triple carbs moved the peak power point from 3400 to just above 4100, with power curves showing little benefit to reving beyond 5000. This was with splash oiling!

The other day I came across a neat site that is dedicated to really early racing:
Race Cars of the 1920\'s and 30\'s
it inlcudes links to the some great old engines:
Miller-Offenhouser Junior Special
Vintage Auto Racing Engines
how about racing with half of a Hispano Suiza flat eight from WWI era fighter? The result is 359 cubic inch inline 4 with a five inch stroke!

[Linked Image from 49fastback.com]