Calm down Wayne, it sounds like this ain't your first rodeo so you should know anything other than stock requires work no matter how much it is considered "bolt in". Most goes don't have welders and fab skills (and some don't have internet, my point is most guys don't have everything some of us others have) so the later truck 9" is a bolt in for them. Like me and several others said earlier, take the 9" and open it up, you will never know what kind of shape it is in until you do.

On a lighter note I got a chuckle out of your switching to 3.55 gears for performance, that is a cruising gear for my vehicles.

Anyway have a good Christmas.

 

1957/72 F100 9" is what you want, not just 1967/72. In 1973, Ford increased the distance of the rear frame rail width behind the cab from 33 1/2" to 37 1/2."

1957/67 F100 9" has 28 spline axle shafts and 11" x 1 3/4" rear brakes.

There are TWO DIFFERENT 1968/72 F100 9's, both have 11" x 2 1/4" rear brakes, but one has a 9 3/8" ring gear, 31 spline axle shafts and Traction Lok.

I can tell by the design of the carrier (pics in post 1) that this rear axle has a 9" ring gear, 28 spline axle shafts.

9" rear axle ID tag located under one of the bolts (usually at 5 o'clock) that retains the carrier to the housing, but by now...many are missing.

VIN does not contain AXLE code, it's stamped on the Warranty Plate, located (1963/72) on the left door face below the latch.

11 digit VIN stamped atop the right (passenger) side frame rail, either partially under or ahead of the cab. The last 6 digits decodes to the year.