[Brent67CAT]

I have a 67 4DR HT Catalina and have the same problem. But I do have the shop manual for 67' maybe this will help abit. The manual covers Tempest Models
Series#
23300 Sports Coupe
4-Door Sedan
Station Wagon

Tempest Custom Models
Series#

23500 Sports Coupe
Hardtop Coupe
4-Door Hardtop
4-Door Sedan
Convertible
Station Wagon
See if your style number matches any of these.

*** The following is straight from the manual:

Nine different axle ratios are available for the various car models. They can be identified by the code stamped on the rear L.H. axle tube adjacent to the carrier, or on the left rear brake drum surface. Three differential cases which differ in ring gear mounting dimensions are used on 1967 models: One for the 2.56 and 2.78 ratios, One for the 2.93, 3.08, and 3.23 ratios, and One for the 3.36, 3.55, 3.90 and 4.33 ratios. When changing axle ratios, be sure to use the proper differential case.

For the 2.78 ratio the code is Std. Diff.Code=WC
Lock Diff.Code=YC

I don't know if this helps out in your search, but if you need any info from the 67' manual just ask and I'll look it up. Brent67CAT