The center to center on the spring perches should be 43" for an A body housing, and it would've only come with small bolt pattern axles, unless changed out for aftermarket! Don't be fooled by the 65-67 B body housing, which is only an inch wider than the A body unit, but has large bolt axles! Also, the brake line distribution block on a 1969 and earlier A Body axle will be up on the center hump a little, whereas the 1970 and later unit will have the block down on the drivers side axle tube a bit! This may cause a problem with the length of the rubber hose needed!