i have a stock 8 in and im going to be looking for 8" rear ends with gears/posi at bone yards, but how can i tell if its an 8"?
the easyest way is if you can put a socket on the bottom two nuts that hold the thirdmember into the housing. if you can only get a wrench then its a 9"
Ford rear ends usually have a tag of one of the nuts that hold the thirdmember in. The tags usually say the gears rear end size and i believe serial number something in the for of this: Serial: XXXXXXX99 (just symbolizing) Size: 8.0 (9.0, 8.8) Gearing: 3.73 I'm not sure if it helps, but all the fords i have owned i have decoded in this way My maverick came with the 8in rear end with 2.79 gears, and my F-150 has an 8.8 with 3.33 gears and i have always gotten them off of those metal tags. I have also decoded some 9in rear ends for some friends of mine that way. If you can get your hands on a old chiltons manual they will tell you everything you need to know.
I checked on my car to make sure. there are two rows of stamping the tags the top row is serial numbers i belive and the bottom row will tell you everything you want to know. the first number is gearing, second number is size and i don't remember for sure what the third one is. http://www.woodyg.com/fairlane/finfo/fordrear5.gif this link shows a good description but i think thats older rear ends because where that one says date mine says the size. hope it helps
Good post just wanted to add this just incase someone who see's this goes 9" hunting Also to anyone who is looking for a 9" avoid the 9.3 (9-3/8) rear The 9-3/8" differentials are strong, but there's no aftermarket gears for them.these can look like a 9" to the naked eye and is usually found under fullsize car in the mid 60's-mid to late 70's Easy way to identify these are the "rounded rib" at the top of the center section
