54 Firewall Mounted Brake Pedal?

[69l46vert]

Mocking up my 54 project. My plan is (was?) to use the stock clutch pedal/pivot assy and get a CCP firewall mounted M/C pedal/Booster. I didn't want to go with a frame mounted M/C since my newly built tranny Xmember will interfere with the booster. It's 4wd so the crossmember supporting the t/case adapter is right where the booster wants to go.

My questions are these; CCP firewall boosters only fit 47-53. Can someone tell me the difference? Has anybody used/modified the 47-53 ccp firewall assay on their 54?

I thought i had a great plan until I went to buy the CCp assay and realized it don't fit 54's. Looking for some solution. Thanks, Rick