Technical A different question on brake pedal ratio

Alright I've been working on the dash (38' ford) in my 31 tudor and setting up the 1" tube cage in the cowl to mount my under dash master cylinder, steering column etc to and trying to figure out how it's all going to fit and mount.

I'm using a corvette style master and I have the 90° pedal****embly from a dodge van that I will cut down to fit nice and snugly under there.

I will be running front disc, rear drum and MANUAL brakes so I already understand a ratio of 6 to 7:1 is where I want to be BUT here is my question!

All the charts on ratio's I looked show a hanging pedal with the top hole being the pivot and the lower hole being the master cylinder and the math they show for this set up, so with mine it's the opposite, the upper hole will be the master cylinder and lower hole the pivot. So how do I figure out the ratio properly?

I'm great at math and numbers but for some reason I just can't get my head rapped around it. So if I have 2" between the holes, top master cylinder, bottom pivot, would I need 12" from bottom hole to brake pedal to get 6:1 ? Am I correct?

Thanks guys, getting old I find simple problems become harder for me to figure out !!

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yes

 

Yes.
https://techtalk.mpbrakes.com/how-to-series/correctly-calculating-pedal-ratio

Two pedal drawings at the top of the article. Yours is the second drawing, just upside down. The math is the same.

 

What is the corvette style MC piston diameter? Was the Corvette style MC made for rear drum brakes or discs? What rear drum brakes do you have? Diameter, width of shoes, and diameter of the wheel cylinders. Are your front calipers 2 or 4 piston?
All these items are important when engineering your own system. I have non power disc/drum and each question I’m asking you was asked of me.

 

Thanks guys!!

Front gm metric calipers 2.38" piston
Rear ford 15/16" bore wheel cylinder
Ford 11" x 2 1/4" brake shoes.


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My MC bore was 7/8”. I’m sure the Corvette style is larger if disc/disc. My ratio was also 6-1. If your MC is 1”, you maybe ok but 1-1/8” may take more foot pressure than you will like. Rears are the same..Good luck.