Quote:so your saying that my yukon axles are gonna set my drums out further so the 10 inch by 2 1/2 drums would work and the shoes would only use up part of the drum.
iirc there was a year or two of 7&1/4 BBP drums that used the 1&3/4 (SBP) shoes that you have & would fit your 8&3/4 IF your custom axles were made with the 1&3/4 shoe standout but they are extremely hard to come by. I'm assuming the Yukon axles used the std BBP brake standout distance which means you would want any std BBP B or C body 10" or 11" brake setup & I think their shoes are 2&1/2 and there were 3" setups (C body 11" I believe) out there
Years ago I went through this with Strange Engr., I had them make me a set of 35 spline axles to fit the stock A body housing with the stock brakes(there lighter than the other brakes on the E and B body cars 
) They used the B body axle blanks that have a larger outside diameter on the axle flanges so the stock A body 10x1 3/4 wide brake drums wouldn't it over those axles until I had the axle O.D. cut down to fit into the stock A body rear stock drums, $75.00 later 
My message is you can make many things fit, as long as your willing to have them modified My car ran in the low tens and high nines at or faster than 126 MPH with those rear brakes and the 1973 and later single caliper A body front discs I never had a problem stopping that car at the races or anywhere else 
Quote:Almost all custom BBP A body axles are specifically made for the std B/C body brake setups which means you would only use any BBP complete matched brake setup (drum/b plate/shoes/hardware) either the one with 2&1/2" shoes/drums or the 3" shoes/drums. I found a note here that the brake overhang (brake gap) is 2&1/4" on the A body and 2&1/2" on the B body. Not sure if that is measured by hooking a tape over the wheel flange then back to the housing flange which'd be on the inside of the retainer flange but you might play with your tape & see what you have & if you have either of those dimentions.
so your saying that my yukon axles are gonna set my drums out further so the 10 inch by 2 1/2 drums would work and the shoes would only use up part of the drum.
