I decoded the tag and I have a cutlass supreme holiday coupe. It's a ac car with a 4bbl. Did those come with a turbo 400 and a 3.08 12 bolt posi? The trunk has the 12 bolt posi sticker but the trunk bottom is red and the trunk is blue and matches the rest of the car in wear. Is the strato bench seat with a arm rest pretty common?

 

Most Holiday coupes were 330 v8's and had a 2spd Jetaway. A lot had the bench seat with center armrest. It's not a 12 bolt posi like a Chevrolet unless it was put in there, should be a 3.08 open with a 12 bolt cover and 10 bolt ring gear.

 

Turbo 400 was not available with the 330 engine in the 67 Cutlass only the 2 speed auto or 3 or 4spd standard trans.

 

The TH400 was only installed behind the 400 motor, which was optionally available in the 1967 Supreme with the Turnpike Cruiser package.

As noted above, this is NOT a "12-bolt" axle, despite the number of bolts on the cover. The number actually refers to the bolts holding the ring gear, which on Chevy axles coincidentally matches the number of bolts on the cover. A real Chevy 12-bolt has an 8.875" ring gear. Your Type O axle has an 8.5" ring gear held with ten bolts. No, it has nothing in common with the Chevy ten bolt axle, either.

 

It could also have a 10 bolt in several different ratios