someone school me on my A833 for my swap Please

Dave
I tried swapping my O/D stuff into cast iron 2.66 cases. In neither of the two that I tried would it go. In both cases that big cluster gear hit the pass side of the case long before the pin lined up.I dont remember the amount of interference, only that I was unwilling to grind that much out. Instead I had the al.box machined to accept a steel front bushing.Later I bought thePasson Al.box(very nice BTW)
My question is; do you think my cases were the exception?