Will the fan of a A1176 fit on a A1283 Model?
Same as above
Looking at www.mac-pro.com the two fans are enough different to not work properly. The one for the A1176 (1.6 GHz intel Core Duo) has a lower air displacement than the one for A1283 ( 2.0 GHz Intel Core 2 Duo). If you were to put the older one in the newer machine you would most likely run into air flow issues. The physical hight is less on the one for the A1176 so it may fit but not worth the overheating issue.