Topic: 1968 Mercury Cougar 390 / 427 / 428CJ Driveshaft early VS late

[RoyceP]

During the 1968 model year we have determined that the driveshaft design for 390 / 427 / 428CJ cars equipped with C6 transmission evolved from a straight 3" diameter tube to a more robust design where the tube is stepped up to a larger 4" diameter near the front and then tapered back to the smaller 3" diameter at the rear. Both drive shafts use the same universal joint and the same yoke at the front. Both driveshafts have the same color codes / stripe identification.

The color code ID is (from multiple build sheets and confirmed by original examples) Light Blue / Dark Blue / Dark Green.

Here is an early example from a 390GT powered 1968 Cougar. The car was actually produced (Marti Report) February 27, 1968, five days behind schedule. You can see the location of the three ID stripes and the pale yellow stripe located at the rear end.

This shaft had been plastered with rattle can flat black primer by a previous owner. The photo here was taken after chemical stripping.

[RoyceP]

This is the later style tube. This one has since been restored to duplicate the location and style of the original markings. This particular car is a 428CJ actually produced May 13, 1968 - one day ahead of schedule. We do not know if the later style of driveshaft is related to the April 1968 release of the 428CJ or not. Note that the position of the ID stripes has changed, they are now towards the drive shaft's front.

[krelboyne]

Dearborn vs San Jose? We should rule out that it may be a plant supplier difference? Or do we know that they came from one supplier for both factories?

[RoyceP]

All cars that I have had or seen are Dearborn built. No idea if SJ did or did not do the same thing. This research started with GT-E's but maybe 15 years ago I realized that the same was true of early vs late GT390 cars as well. No idea if Dearborn X codes are the same as I have not personally checked, although I have owned a few but not thought to look.

Dearborn vs San Jose? We should rule out that it may be a plant supplier difference? Or do we know that they came from one supplier for both factories?