1968 Cuda 8 3/4 rearend axles

So I'm rebuilding the 8 3/4 sure grip rear axle on my 68 Barracuda. I'm upgrading to 4.5 inch lug bolt spacing and have to replace the original 4 inch spacing rear axles. The guy working on my rear end says he can't get 4.5 lugs on new axles for A bodies but can get B body axles to fit. Do I need to get B body axles? Sounds like if I get B body axles that I will have to shorten them to fit the A body housing. Does anyone have any guidance for me on this?

Thanks,

Eric