Drums are the same, so no problem there, 8 1/4 and 9 1/4 are the same dimension for drive-shaft length, so that is not an issue, I just needed to know if the axle shafts would swap or am I looking for different axles or bolt pattern adapters/spacer, which I really didnt want to use, but considering what I will do with this truck, may not be an issue. I don't tow anything heavier than a 14' aluminum v-bottom much more than 10-15 miles 3-4 times a year, primary use of this truck is just gravel road travel once in a while. Aluminum bolt pattern adapters may be an acceptable issue just to get the sure-grip and greater strength of my 9 1/4? /although I have never been real comfortable using them in the past, I have never had an issue with them either. I'm just trying to get the better gear and sure-grip into this truck as easily and cheaply as possible.