4.10 Rear-Axle Gear Ratio Tag fits 9 3/4 Dana 60 Mopar
A Dana 60 that has been through fifty years of rebuilds, cover swaps and parts-car shuffles rarely keeps its original ratio tag, and a missing tag is one of the first details a sharp-eyed judge or buyer notices under a B-body. This reproduction replaces that lost piece of identification with a small aluminum plate stamped "4.10," matching the gear set inside the housing. It is made in the USA and costs far less than hunting down a legible original at a swap meet.
Where the 4.10 Dana 60 Fits In
Chrysler reserved the Dana-built 9-3/4 inch rear end for its heaviest-duty applications, and a 440 or Street Hemi car with a four-speed should have one under it. On 1966-1970 B-bodies the housing measures about 54.9 inches, while 1971 B-bodies use the wider 56.5 inch version shared with 1970-71 E-bodies, so the two are not interchangeable without modification. Sure Grip units in these axles were Power-Lok from 1966 to 1969 and Trac-Loc from 1970 on. A 4.10 gear set is the steep, drag-oriented ratio in this family, and a correct tag tells anyone under the car exactly what the rear end was built to do.
Confirm the Ratio Before You Hang the Tag
Because housings and gear sets get swapped over the decades, it pays to confirm what is actually inside before installing a 4.10 tag. Mark a rear tire at twelve o'clock and put a reference mark on the driveshaft or pinion yoke, then turn the tire one full revolution and count driveshaft turns. Slightly more than four turns points to a 4.10 set, while about three and a half suggests a 3.54 or 3.55. Verifying the housing itself is simple as well, because the 9-3/4 uses a 10-bolt rear cover with roughly six uneven straight edges.
What You Get
Each order includes one aluminum tag stamped 4.10 (store SKU FR10). It is intended for owners finishing a correct restoration, those preparing a car for judging, and anyone who rebuilt a Dana 60 with fresh 4.10 gears and wants the housing marked to match. The tag is an identification piece only, so it has no effect on how the rear end performs.
Frequently Asked Questions
Will this tag work on an 8-3/4 rear end?
This listing is for the 9-3/4 inch Dana 60 used under the Charger, Coronet, Road Runner and GTX models in the fitment list. Check your housing first: the Dana 60 has a 10-bolt rear cover with about six uneven straight edges, which makes it easy to tell apart.
Is this an original Chrysler tag?
No, it is a new reproduction made in the USA from aluminum and stamped 4.10. It is meant to replace a tag that is missing or too damaged to read.
How do I confirm my car really has 4.10 gears?
Mark a tire and the driveshaft, rotate the tire one full turn, and count driveshaft revolutions. A little more than four turns indicates a 4.10 ratio, while about three and a half indicates a 3.54 or 3.55.
