Over revving....

[happycamper]

I have an oozing, drippy 9" with 3.50 gears in the back of my new project, a 71 F100. Would like to know from anyones experience what I can stuff in there that will be low hassle (direct bolt in fit?) and get me low low rpms on the freeway? I don't mind switching to a newer axle, however it seems that there is some sort of issue with the pinions changing on newer rearends (read on other posts). My truck is a cruiser not a hot rod, so not worried about high performance.

I live in California where everyone drives 65-80 MPH on the freeway and if you can't keep up, you are a hassle to everyone. Looking to find some gears in the 2.73 - 3.00 range. That should get me there. Any pointers on years, axle codes, year range, etc. would be fantastic. Thanks.

[BobbyFord]

Any 9" pumpkin will bolt in and work so long as the axle spline count is the same. Scout the boneyards in your area. Mid and full size Ford cars had 9". Look in 60's, 70's pick ups and cars...

[Caseys71]

Any 9" pumpkin will bolt in and work so long as the axle spline count is the same. Scout the boneyards in your area. Mid and full size Ford cars had 9". Look in 60's, 70's pick ups and cars...

, As far as seeing what ratio the axle's got you can look on the axle tag. On the lowest line of the tag the first 3 numbers on the far left will give you the axle ratio. Your spline count is most likely 28 although it could be 31 (28s are much more common though, and you can verify with the method listed below fairly quickly, or since you've got your truck at your disposal it would probably be simplest to try and decode the axle tag and see if it is a 28 spline before pulling an axle) only way to verify that the 3rd member you pull has the same spline count is either by decoding the axle tag (may or may not give you the spline count) or by counting the axle splines (easiest/quickest way to do that IMO I think would be to pull a drum, remove the 4 retaining bolts that hold the axle shaft to the backing plate and pull the axle to count).

[survivorman]

2.73s are easily found in full size cars. Also look at the brakes. Expensive cars got more upgrades, and those cars usually weighed more too.

Large sedans had 11 inch brakes, and many station wagons had 12 inch brakes or HD as it would appear in a brochure.

I would look for 68-78 range becouse of the big bearing 9 inch and the relative size of the full size cars in those days in a better match.