It seems many people believe that, in life, if a little is good, then a bunch is bitchin'. But sometimes the opposite may be true; sometimes less is really more. Take rearends, for example. The standard non-independent rearend used under most cars in the hobby is the 9-inch Ford. They're tough, a variety of gear ratios are available, and they look good without all the brackets and bolts other rears have. But there is an alternative to the 9-inch-its sibling, the Ford 8-inch. And, in some cases, it may be a better choice.
While there is no question the bigger 9-inch is superior in the strength category, the 8-inch shouldn't be totally disregarded. Both rearends share the same excellent design and both use 28-spline axles. Though 9-inch rears can be equipped with much stronger 31-spline and larger axles, in most cases, the smaller 28-spline setups are more than strong enough for 300hp cars that see street duty.
When it comes to third members, the 9-inch is certainly stronger and there are more gear ratios available. However, for street use, the 8-inch still offers plenty of choices because 2.79:1 to 5.43:1 gear sets are available. As with its bigger brethren, a variety of disc and drum brake options are available for the 8-inch, and the housings come in a variety of widths.
To sum it all up, the 8- and 9-inch rears share the same basic design, they look similar, and have a lot of gear ratio and brake options to choose from, but the 9-inch is stronger. So why would anyone choose an 8-inch? That's a good question with a simple answer-weight. A typical 9-inch tips the scales at around 205 pounds; an 8-inch is around 160. That's a 45-pound difference, and that's really significant when you're trying to reduce a car's unsprung weight.
Controlling a car's unsprung weight (the total weight of all its parts not supported by the springs, i.e. wheels, tires, rearend housings, front axle, brake calipers, etc...) is key to ride quality, and with less unsprung weight, the car handles noticeably better. But if you really want to take advantage of the weight- savings potential of the 8-inch, check out the Currie Alumin-8 gear case. This new aluminum looker is precision cast, machined from a 206 alloy, and weighs in at a mere 10.5 pounds compared to 23.5 pounds for the stock Ford 8-inch center section. And, as far as eye appeal goes, nothing can beat the looks of a polished Alumin-8.
Currie's engineering department has also built a better 8-inch pinion support, precision-machined out of 6061T-356 aluminum and houses a larger rear bearing. This unique design incorporates a flow-through oil passage to bring cool oil to the front pinion bearing. Currie believes its billet pinion support is more than 25 percent stronger than conventional and stock units. It will fit all 8-inch gear cases and is available in a polished (PN CE-4033P; list $114.95) or red anodized finish (PN CE-4033D; list $99.95).
What it comes down to is this: If you're running a lot of horsepower and big tires and like to drop the hammer from a standing start, the 9-inch is the way to go. If you're concerned with ride and handling and you have a light car in the area of 2,500 pounds or a bigger car with a mild engine and an automatic transmission, then an 8-inch will fill the bill quite nicely-proving yet again, less really is more. The Alumin-8 aluminum gear case (PN CE-4026A) lists for $389.95 and is available exclusively from Currie Enterprises and Currie dealers.