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tdangle · 12-01-2021, 11:21 PM

Converting a 70 C20 power drum to power disc. Basically changing it to a 71 C20 with power disc brakes. Swapping out the dual 8" booster to a 10" dual booster as stock with a 71 C20. Problem is the mounting Frame is 3 1/2" from the firewall and it looks like it needs to be 5". the rod coming out the back of the old booster to center pin is 3 1/4" the new booster's rod is 4 7/8" to center of the pin. Did GM change the bracket to a longer one? Can anyone verify?

12-01-2021, 11:21 PM	#1
tdangle Registered User Join Date: Mar 2005 Location: Jurupa Valley, Ca Posts: 1,211	New issue with disc brake conversion Converting a 70 C20 power drum to power disc. Basically changing it to a 71 C20 with power disc brakes. Swapping out the dual 8" booster to a 10" dual booster as stock with a 71 C20. Problem is the mounting Frame is 3 1/2" from the firewall and it looks like it needs to be 5". the rod coming out the back of the old booster to center pin is 3 1/4" the new booster's rod is 4 7/8" to center of the pin. Did GM change the bracket to a longer one? Can anyone verify? __________________ Terry 1970 Custom Camper/C20 , GM Crate 350/7004R, Dana 60, factory AC