The days of going to your local wrecking yard and picking up a good Ford 9-inch rearend for your hot rod project are coming to an end. That sturdy and versatile unit was last produced for passenger cars in 1981 and in pickup trucks in 1986. Considering that 9-inchers are the most used rearends in nearly every form of racing and most high-performance street vehicles, it's not hard to see why they are becoming scarce commodities.
Even when you do find one, you have to determine whether the tubes are straight or the axles bent. When you figure in the time that it takes to refurbish an old rusty hulk and transform it into a usable unit for your rod, you might wonder if there's a better way to find a rearend. One answer would be to use a 9+ rearend from Currie Enterprises.
Despite the dwindling supply of salvaged 9-inch rearends, Currie's main business is remanufacturing them for hot rods, race cars and off-road vehicles. The company refurbishes more than 200 used Ford 9-inch rearends a month. Currie began in 1959 rebuilding rearends for electric industrial carts, and started specializing in 9-inch Fords in 1964.
By the mid-'70s, the company had a stockpile of over 50,000 used rearends spread over two storage lots. Today, it has only about 2,500 backup units left on hand. It buys them in Mexico, Canada and from all over the Midwest US. Passenger car rearends are preferred over those out of pickups because the car rearend in most cases still look new. Even though truck rearends' center section and the gear case are usually usable, because they run more miles and haul heavy loads, the axles, brakes, and gears are trash. Three years ago, Currie was paying $20 for a core housing. Now, it has to pay $60 and it's going to keep buying them until there are not anymore left. Currently the company can only obtain about a quarter of its needs. Supplies are about dried up and there are simply not enough Ford rearends left to meet demand.
About two years ago, Currie could see the writing on the wall and decided to start manufacturing its own rearends. "At the time, all the aftermarket parts that were available were for high-end drag racing," explains Ray Currie, one of four sons who now works in the business. "There were no new stock replacement parts for street use; everything was used. So we decided to make two new rearends. The first was the early-style, smooth-cover "hot rod" housing that was used from '57 up to '64. It is the most difficult to acquire right now. In addition, we also make the Torino/Ranchero (notched) heavy-duty housing. We beefed up both housings by making it out of thicker material. The Ford units were 0.180 inches and ours is 0.200 inches. The cover is also about 0.020 inches thicker than stock. The profile and basic shape is almost identical to the original. We also use a little bit better steel than stock Ford units do.
"The original Torino/Ranchero housings used a 3 1/4-inch tube that was swedged to fit the housing. We wanted to use a three-inch tube because that is what all the mounting brackets are designed to fit. We remade the housing to except the three-inch tube without any swedge. Some people like the round cover; some like the new style cover—so both are available on this housing."
When Currie Enterprises decided to make the gear case, it did not want to re-invent the wheel. Ford's basic design was good, but Currie wanted to make it better with a few small changes. The most obvious one is the use of stronger nodular iron instead of gray iron used by Ford. Gray iron has a tensile strength of 30,000 psi, while nodular iron is 65,000 psi. Currie also used nodular iron in the double-ribbed carrier cap. Ford used gray iron in all its single ribbed caps, even on the factory nodular iron cases.
"Most of the failures that happened on stock gear case were in the carrier cap or the pocket bearing," notes Currie. "So those are the two areas where we added extra material. We also extended the rib on the outside that supports the carrier caps. This gear case is designed to be a stock replacement. It is not directed to high-end drag racing. It is targeted to people with 500 horsepower and less."
Currie Enterprises also manufactures a 9+ "Race Case" for street cars that are in the 500 to 900 horsepower range. It too is made of nodular iron, but completely reengineered to handle the higher power demands. It also uses billet spanner nuts and chrome-alloy carrier caps.
Currie pointed out, though, that many of the late-model racers (a 3200-pound car with 500 horsepower) running at Irwindale Speedway are using the company’s street case because it is made of nodular iron and lighter than some racing cases.
As part of the 9+ manufacturing program, Currie also makes two pinion supports. The stock support and the big-bearing, Daytona-style pinion support. The company also manufactures both open and posi-traction carrier assemblies and two different yokes available, the 1310 and 1330 series and soon a 1350 series. In addition, there are two different styles of housing ends.
For its refurbished 9-inchers, Currie does not waste any parts of the used unit. For low horsepower applications, the company will re-machine every dimension on the axle, weld up and re-drill the boltholes, change the register diameter, change the flange diameter, regrind the bearing journal, and cut and re-spline the axle. Currie is basically using the axle as a forging and re-machining every aspect of it.
For higher horsepower applications, Currie makes all-new axles on CNC machines. The company is said to be the largest aftermarket axle manufacturer in the world, making over 30 specific axles for different applications. Currie offers a remarkably wide range of gear ratios as well. Just try and find that sort of selection in your local junkyard.
