48degree blocks and heads

I'm trying to find out what is the difference between 48 and 59 degree blocks and heads are. From what I gather the 48 gives better geometry by having the pushrods closer toward the middle of the motor right? If so then what's the diff. between say W2 48 heads and regular W2 59? There is no difference in intakes that I know of so the heads have to have the same intake face placement. The rocker stands or pedestals have to be in the same place right or is the rocker arms between the two heads different length? Thanks in advice for the help.