69 GT500 A/T question

[kasearch@ix.netcom.com]

Is there anything different on a Shelby C6 vs. a stock Ford C6?  Are they aluminum body with cast iron tail shaft?

[Coralsnake]

Yes, there is a difference and it is aluminum with a cast tail.

The main difference is the case is machined to receive a "R" servo

[KR500]

No! a 69 GT500 C6 is exactly the same as a stock Ford  428CJ C6. Yes the CJ C6 is different than other C6's but the Shelby C6 is not unique by it's self.  Yes all C6's are aluminum bodies. 428 CJ's use a cast iron tail shaft housing were most non CJ applications use an aluminum tail shaft housing.

[pbf777]

     Don't forget the additional clutch plates and 4-pinion planet gear set, probably from the "Camper Special" trucks.     

     Scott.

[Bob Gaines]

No! a 69 GT500 C6 is exactly the same as a stock Ford  428CJ C6. Yes the CJ C6 is different than other C6's but the Shelby C6 is not unique by it's self.  Yes all C6's are aluminum bodies. 428 CJ's use a cast iron tail shaft housing were most non CJ applications use an aluminum tail shaft housing.

To add the servo body opening on the CJ C6 case is larger on the CJ case vs the smaller non CJ C6 because of the larger R marked servo. The CJ main case is special to CJ .The case is not Shelby unique as has been mentioned.

[pbf777]

     Well, to the best of my knowledge, the case casting was not different, nor the case boring diameter, but it was machined differently with a smoother finished bore to accept the "R" servo piston providing the proper surface as the release "0"-ring sealed and its' motion is within this case bore versus within the covers' provided cylinder.  My observation has been that at some time post the initial "special" machining of the cases for the CJ intended applications, not saying all, but it seems this operation was standardized as it is not uncommon to find units which will accept the "R" servo even though not originally "CJ" units in 70's production C6's. And further, if this surface texture in some stray C6 is for some reason is deemed not acceptable, it has proven commonly possible to just (easier said than done) polish this surface for the "O"-ring survival and insert.     

     O.K., I've been wrong before, ...............hit me with it!       

     Scott.

[Bob Gaines]

     Well, to the best of my knowledge, the case casting was not different, nor the case boring diameter, but it was machined differently with a smoother finished bore to accept the "R" servo piston providing the proper surface as the release "0"-ring sealed and its' motion is within this case bore versus within the covers' provided cylinder.  My observation has been that at some time post the initial "special" machining of the cases for the CJ intended applications, not saying all, but it seems this operation was standardized as it is not uncommon to find units which will accept the "R" servo even though not originally "CJ" units in 70's production C6's. And further, if this surface texture in some stray C6 is for some reason is deemed not acceptable, it has proven commonly possible to just (easier said than done) polish this surface for the "O"-ring survival and insert.     

     O.K., I've been wrong before, ...............hit me with it!       

     Scott.

You may be correct that later C6 cases may be modified to accept the R servo . I was talking about castings with the date clock on the case appropriate for a 69 GT500 C6.

[pbf777]

     Well, to the best of my knowledge, the case casting was not different, nor the case boring diameter, but it was machined differently with a smoother finished bore..................

     Scott.

You may be correct that later C6 cases may be modified to accept the R servo . I was talking about castings with the date clock on the case appropriate for a 69 GT500 C6.

      Yes, I understood; and it would seem actually that it would be more often the earlier cases prior to the development of the "R" servo piston appearance that may require a smoothing of the surface to allow the sliding of the "O"-ring without excessive wear. The several different servo assembly/cover units that were produced are to the best of my experience all interchangeable among any of the C6 cases as the boring to accept such with its' "O"-ring seal is standardized; just that the original intention was for this "O"-ring to act solely as a stationary fluid seal versus a sliding one within the case itself, hence the requirement to insure a compatible surface finish.  This consideration would have proven very cost effective as no real significant engineering change would be involved, only a change of tooling, or perhaps just a reduction in said tooling traverse rate as this boring was executed. Also the universal application any C6 case would be maintained, and as a consolation the related machining operation that was otherwise required within the cover was omitted, but a unique, but simplified with only one piston bore versus two cover casting was required, and of course its' corresponding piston, hence the "R" servo assembly.   

      Well, it's the world as I seem to understand it anyway!     

     Scott.

[68stangcjfb]

I've seen several C6 cases. In my observations, sometime in the '71 or '72 model year, the case bores started getting machined all the way down to the bottom so they will accept the R servos. On the earlier cases, the bore is only machined about 3/4 of an inch down to accept the cover O ring.