8.25 8 1/4 Rebuild and modification

Custom 8 1/4 Rear-End Install - Project Build - Mopar Muscle Magazine
Installing An 8-1/4 Rearend To A Muscle Mopar

Written by Brad Ocock on March 1, 1999

Tom Rounds - photographer;

When it comes to making your car perform better, there’s always a set order for performance modifications; front-to-back. We all start under the hood (usually with carb/ intake/headers, often followed by a cam swap). For those who like to row their own, a performance shifter is installed, maybe a clutch; automatic guys modify the valve body and later install a high-stall converter. Last on the list has always been the rearend. A lot of post-muscle Mopars rolled off the line with a standard, “small” not- built-for-punishment 8 1/4-inch rear end. The 8-3/4 is far more popular by virtue of it’s easy to set-up drop-out carrier, ease of gear changes (need a different ratio? Just swap the carrier!), no C-clips, stout construction and, of course, the strength of a larger ring gear. If you really want strength on an unparalleled level, you can step up to the legendary Dana 60. Able to handle torque output on the scale of diesel locomotives, the Dana is the last word in rearend strength. During the halcyon days, all it took to get one as original equipment was checking off the right boxes.

If your current street stomper came equipped with an 8-1/4 rear, standard thinking goes something like this — If it ain’t broke, don’t fix it. When it breaks, upgrade to an 8-3/4 or Dana. We’ll build the engine and trans, but forget about the rearend. When it breaks, we call the car all kinds of nasty names, tow it home, yank the rear and replace it. Most project cars are high-mileage cars, but the engine and trans have at least been gone through, if not outright rebuilt. When’s the last time you even changed the fluid in the rearend? Then you get mad when the poor thing breaks after increased horsepower from the front of the car on top of years of neglect....