I am going to make a top hung pedal box to make with theaster cylinders I currently have an wondered if anyone had done this before and how they went about it.
There’s a set of plans in the Haynes Roadster manual that could be inverted and adapted?
I sketched out what I wanted, then made a mock-up frame using thin MDF to hold the pedals (from an old Escort).
After fiddling around and making adjustments I drew up final sketches and transferred them to metal sheet.
Have a look on Wilwood, Tilton, AP Racing, etc. sites as they have drawings for their pedals.
If these would save you some time and/or hassle, I do have a top pedal set (brakes and clutch) on a shaft. There's a related accelerator pedal
(more of an addendum) which is lurking somewhere... somewhere...