The big bolt MC has to be "fail safe"- - - - able to move enough volume of fluid to apply all the brakes, with or without the Hydrovac working. That requires a bigger bore and a longer stroke than the pickup cylinders.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!