Since I wasn't born with the knowledge that there are three (or more?) different 'types', not to mention lengths, splines, etc., I had to do a lot of research to determine exactly what mine is (don't expect a happy-resolved ending to this novel - I STILL don't know all about the one in my Mav).

I'm about to put 600 h.p.'s (with a transbrake) to the rear so I 'really' need to know which 9" I have. Only the 'big' ford rears will withstand repeated launches with that much power.

I searched a lot of links and found the following ones
I found the following links to be helpful in learning more about the Famous Ford 9".

I'm posting this information to newbies like myself with the intention of saving a lot of time and to help enlighten others intrested parties.

Two major finds were 1)How to quickly determine which 9" Ford rear-end I'm looking at. The image shows the distance between the bolts that hold the brake housing (plate) onto the axle housings. These dimensions can easily be measured by dropping to the ground and taking one quick measurement (two, if you want the warm fuzzy feeling).

2) Also, as far as the gear ratio is concerned, I learned if you DO NOT have a positive traction rear-end or a tag with codes, lift both rear tires off the ground, rotate one tire a total of ten times while counting the number of times the opposite side tire turns. Ex: Tire 1 is rotated 10 times. The opposite tire rotates 25 times. The gear ratio is 250:1. (I haven't tried this so, please, if you know this info to be eroneous, reply with correction).

Anyway, I hope this info helps save time with fellow Mav/Comet owners.

Keep up the great posts everyone,

Thanks for the post.

Rick

Housing Identification
"http://hiqties.hypermart.net/9inch.html"

The Number 1 Question - How do I Know If My Rear Is An 8" Or 9"?????
"http://www.ridgenet.net/~biesiade/Fordrears.html"

Instructions on installing either 8" or 9" gears
"http://www.ridgenet.net/~biesiade/gearinstal.html"

Where To Find The Nine Inch Rear Axle and other stuff
“ http://dfwmotorsport.com/Fairlane/9inchrearends.htm”