spring perches on a tapered sleeve rearend ?

[blazer2007]

I came across a ford 9 in. rearend which is the same width and bolt pattern as my chev truck but the rear has tapered sleeve . Could you notch the spring perches to fit and weld them in. I,m just asking cause I don,t know how precise this has to be. Is there some room for error or does it have to be absolute perfect. I don,t really want to put new tubes on. The rear end has new gears and bearings with the right gear ratio I,ve been wanting