The Rearend Debate: Ford vs. Chevy
For the last 50 years or so there has been an ongoing debate between car enthusiasts. Yes, it’s the Ford vs. Chevrolet debate. Well, sort of. There has been a back and forth on which rear end is better, the Ford 9-Inch or the Chevrolet 12 Bolt. We here at Speedway thought it time to shed a little light on the two options, and try and remain unbiased as we do so. So here goes!
First mass produced by Ford Motor Co. in 1957, the venerable 9-Inch rearend has become a standard among gearheads both young and old. The variability of the housing to accept almost any gear ratio from 2.47:1 to 6.14:1 makes it a “go to” housing for those of us who intend on flogging our beasts on the track and then driving it home. This is best served by the removable third member, which makes swapping those ring & pinion gears out so much easier.
A few other advantages the Ford 9" has is that, well, it is larger than the Chevy 12-bolt. The ring gear on the Chevy 12-bolt measures in at 8.875 inches in diameter, compared to the Ford's 9 inch diameter ring. Sitting 2.25 inches below the ring gear centerline, the Ford 9" also benefits from a greater tooth contact patch. Your typical Ford 9" will tip the scales at about 175lbs, before you add the brakes.
Coming along a few years later in 1965, the Chevy 12-bolt saw its widest use in the 1965-72 Chevrolet passenger vehicles. Getting down to brass tacks, the GM design is actually just a little more efficient than the Ford 9 Inch. The pinion on the Chevy 12-bolt actually sits 1.50 inches below the ring gear centerline, resulting in a small horsepower savings through less friction. The standard Chevy 12-bolt weighs in at around 185lbs when outfitted with the usual drum brakes, but hardly anyone leaves drum brakes on a hot rod project anymore.
The Chevy is not without its own advantages when compared to the Ford 9 Inch. The traditional cast iron caps of the Ford 9 Inch are an inherent weakness, and after upgrading to the nodular setup, the retainer and pinion bearings will also need updated to counteract a potential domino failure. In contrast, the Chevy 12-bolt comes standard with a nodular case setup.
Ultimately, you get to decide what rearend goes under your project. Take into account your intentions; do you plan on a dedicated strip machine, or do you want to drive it in poker runs with your buddies? One last piece of advice, and then we will let you get back to your build; remember, it’s your build, not someone else’s. Use the parts that make sense to you. We're always here to help.
Products Featured in this Article
Ford 9 Inch Gear-Style Posi Differential Third MembersView$1,248.99Compare