Axle Identification, late '50s through early '80s
The easiest way to identify an axle is to look at the cover on the carrier
housing:
7-1/4.....9-bolt rear cover.
8-1/4.....10-bolts, evenly spaced, cover is almost perfectly round.
8-3/4.....No rear cover, round.
9-1/4.....12-bolt rear cover.
9-3/4.....10-bolts, cover has about 6 uneven straight edges.
Or, you can crawl under the car to have a look at the casting number. The
following is an incomplete list of common casting numbers
you will find in many junkyards. The casting number is usually found on the
front right or bottom of the carrier housing.
7-1/4
8-1/4
8-3/4
1820657 (small stem, up to 1964)
2070741 (small stem, 1965 and later)
2070742 (large stem, 1957-1968)
2881489 (tapered pinion, 1969-1971)
9-1/4
All of the above axles were available with SureGrip, which is a limited-slip
unit. SureGrip is a desireable option in any axle. If you have the choice
between a Sure-Grip or a non-SureGrip axle, choose the SureGrip. To identify a
SureGrip axle, jack up the back end of the car and turn one wheel. If the
opposite wheel turns in the same direction, a SureGrip unit is present and
operational. If the opposite wheel does not turn, or if it turns in the
opposite direction, it is an "open" or "peg-leg" axle or does not have an
operational SureGrip unit.
440 and Hemi cars with a 4-speed should have the 9-3/4 axle, which was
manufactured by Dana and is known as a Dana 60. The Dana 60 is the most
desireable and most expensive axle for Mopars. The Dana 60 came in two lengths.
The 54.9" axle came in '67-'70 B-bodies, the 56.5" axle came in '70-'71
E-bodies and '71 B-bodies. These two axles are not interchangeable without
modification, so try to stick with the correct length for your car if you
install a Dana 60. The Dana 60 was installed in some '72 and later vehicles.
It was also optional in cars without a 440 or Hemi and in automatic
transmission cars. If you find a Dana 60 in a junkyard, buy it! There were two
SureGrip units in the Dana 60. From '66 to '69 it was called Power-Lok, from
'70 on it was called Trac-Loc. Power-Lok is more desireable for racing. The
two SureGrip units are interchangeable.
The 8-3/4 axle is common in many Mopars, including performance cars. It was not
available on 440 or Hemi cars with a manual transmission. A-body cars up to
'72 that had an 8-3/4 will have a small bolt-pattern hub and will require using
small bolt-pattern wheels. Small bolt-pattern hubs measure 4" between alternate
wheel studs as opposed to 4.5" on B, C, E and later A-body cars. It can be
argued that all A-body 8-3/4 axles are small bolt-pattern, as the 8-3/4 was
built until '72 or so. In any event, be aware that there are two different
axles in an 8-3/4.
Original content © 1995-2006 maxwedge.com and Amalgamated Smike,
All Rights Reserved.
