Try the JEGS catalog. They have brake and clutch pedal assemblies, and the master cylinders that work with them. Be absolutely sure to build in enough bracing that the firewall doesn't flex and crack under pedal pressure. Been there, done that, on round track race cars!
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!