Correct tonneau stud pattern for 427 cobra

[dlampe]

I am interested also. I don't even want a top or tonneau cover but I want to install the pins for the original look. I am looking forward to the rest of the details.

[mickmate]

The door ferrules are like the tonneau/top dilemna. They are really fitted to the car as the windscreen has to be the right location and angle and the side curtains and ferrules are made to fit against it. The ferrules are Austin Healey 3000 front ones I believe. Originals had a 3/8" ID where some aftermarket ones are 5/16". If you want them for the look go ahead but remember when you cut your hand open polishing acros lift a dots "I told ya so!" ouchie.

[gsharapa]

I think the best way to do this if your Cobra doesn't come with one is to buy one as there are companies that sell them (prices around $ 300.00) and then install it. Just as many said in the past on 1,000ssss of posts these cars were pretty much built as one offs and I would not trust measuring one car vs another to get the correct pattern as there probably isn't a correct pattern! Now if you just want to have the studs and no cover guess that would work...

[CSX3183]

I have an original cover, with thge zipper for the roll bar, I will be happy to sell it, as my plan have changed. kathywillets@hotmail.com

[A-Snake]

As noted on the photo, the top stud is the left outboard of the four in line studs. The next lower stud is 6 9/16" away (center to center) and on a line with the corresponding stud on the right side that is 7/8” forward of the 4 in line studs.

There are now five more on each side to locate.

The next one I’ll locate is the one closest to the rear of the door. This stud is 40 1/8" from the front snap mentioned before. It is 1" behind the door edge.

[A-Snake]

[A-Snake]

Next is the location for the second stud behind the doors. It is located 4 7/8" behind the previous stud. The measurement to the corresponding stud on the right side is 52 3/8” (center to center) The distance to these studs from the front snap is 42 ¾”
There are now three more on each side to locate.

[A-Snake]

Here are the measurements for the last three on each side. The image is of the right side. The 4 7/8”, 3 7/8” 3 ¾”, 3 ¾” are distances between studs.

The curvature of the body in the area of these three studs prevents measuring to the corresponding stud on the opposite side.

These measurements are for original Cobras whether they are leaf spring or coil spring. As Jim Maxwell mentioned, original tops can be moved from car to car. When a new top is purchased the lift-a-dots on the top are fitted to the body studs.

Cockpit dimensions of replicas may vary making these measurements useless.

[DMXF]

Originally Posted by A-Snake

:These measurements are for original Cobras whether they are leaf spring or coil spring. As Jim Maxwell mentioned, original tops can be moved from car to car.

Jim - Not trying to take away from the value of your efforts (admirable), but I, along with some others, have found not all original cars share the same exact lift a dot pattern. Tonnaus/tops will interchange with many cars, but there are some exceptions. The differences, from unmolested cars, are usually small (maybe 1/2"?) and seem to be found with certain more outboard pins.

[1985 CCX]

Mike is right however a good reference will make it look right and it is valuable information!

GREAT work guys and thanks for the help.............

[A98Coupe]

A Snake

Thankyou very much for such a comprehensive set of measurements, but can you please confirm what you are using for the datum point? Is it a central stud? On 427's I understood that the rear view mirror was mounted approx. 1 3/4" to the right of the car centreline and the nearest stud is approx. 3 1/4" to the right of centre. I'm guessing the latter dimension by using Jim Maxwell's photo of an original 427. Is your car a 289? because I believe the mirror location and hence tonneau stud positions on the front cowl are different to the 427?

[A-Snake]

Originally Posted by A98Coupe

A Snake

Thankyou very much for such a comprehensive set of measurements, but can you please confirm what you are using for the datum point? Is it a central stud? On 427's I understood that the rear view mirror was mounted approx. 1 3/4" to the right of the car centreline and the nearest stud is approx. 3 1/4" to the right of centre. I'm guessing the latter dimension by using Jim Maxwell's photo of an original 427. Is your car a 289? because I believe the mirror location and hence tonneau stud positions on the front cowl are different to the 427?

Yes I have a 289. They have the mirror centered unlike the 427's. The tonneau on a 289 uses a 'strap' that wraps the mirror stem and snaps onto a male snap mounted just below the mirror. (See pic)
427's have an extra lift-a-dot stud on the front cowl just to the right of the mirror instead of the snap (five studs instead of 4 on 289's) The snap I used as the datum point is centered on the cowl.

[Dan Case]

Not proof on every car for sure but I have tried various original covers, tops, and side curtain sets on CSX2310 from chassis CSX2259 up to CSX3298 and they all fit just exactly the same. Several owners that I know of have tried several tops and covers each on their cars, usually making upgrades from poor condition to better condition ones. Other than the difference in middle snaps between Cobras and 427 Cobras fitments I have seen or been told about have been very consistent BUT these involve parts and cars that have never been seriously damaged or modified or had their skins removed from where AC Cars put them.

In the 1970s and 1980s there was a fairly common practice of welding up the stud holes during car rebuilds or just even repaints so that all the ripples and dents around the typical stud could be worked out. Once the body work was smooth new holes were drilled. Another thing to consider is that very many original cars have had their skins removed and reinstalled during repairs and rebuilds. Some shops mark the skins so they can be put back exactly where they originally were; in extreme cases they carefully drill rivets so they may rewrap the aluminum and use the original holes. Many other places just pull the skins off, weld up all the holes in tubes and aluminum, and put the skins back in some location original or not. I have seen one shop that use to trim most of the aluminum the wraps around tubes off and just weld on new wide strips so they have plenty of fresh material to work with. I seriously doubt these shops get the skins just exactly where they were and how you install a skin that already has holes in it can affect final hole locations a lot in all those compound curves of the rear cowl. Take for example the aluminum left fender on my car trailer. I snagged the fender on some shrubbery and pulled the leading end off. The first three sheet metal screws pulled out of the side wall. The fender was damaged but not creased. I straightened the aluminum out, didn’t leave any noticeable marks on it, but now the screw holes in the fender did not line up with the holes in the side wall anymore because of the slight plastic deformation of the fender during getting damaged and straightened. My solution for the problem was to make the holes the next size larger. If that had been a Cobra skin the top studs would have changed location just a little.

I looked at a CSX22XX car that the owner used locking pliers to jerk the studs out because he didn’t want to take the fuel tank out. The body shop had to fix all the conical volanco shaped holes and drill new ones before paint. I bet the body shop didn’t get the new holes exactly in the original locations.

I personally would be suspicious of an original 1960s car with its holes not where most cars have them. It may mean that car has some unpublished (not everything is in the SAAC Registries) history like the car with less than 1,500 miles I looked at in the mid 1980s? The car was at a well known shop. It was seriously crashed in 1965 by the original owner. The car was crashed and stored in the owner’s garage for the next twenty years before being rebuilt. The chassis required a large amount of repairs including new metal in various places, a replacement body (not an AC Cars skin), all new inner panels, and significant numbers of other replacement parts to replace ones damaged in the crash. I got to see the car in various phases of this work. It looked really nice when done but not much original was left. It was sold at auction for a very high price advertised as a one owner extremely low mile absolutely correct untouched original. It was a one owner car when it went up for sale and it did have low miles but everything else about the advertisement was untrue. Significant portions of what was original went into the trash but unless you visited that shop and watched the car change from mangled mess to auction show piece you might think it was just done differently by AC Cars as an exception.

So many of these old cars were so abused most are not very close to the way they were in the 1960s much less the way they were when new. Originality has become an ‘eye of the beholder’ topic.

[Dan Case]

Somebody asked about the ferrules in doors for side curtains. I can show you the pattern in CSX2310. I did this sketch for a CSX24XX car owner last year. The center line is for the holes and not the top of the door. Measurements were just done with a tape measure. The information was good enough for him to pick a set of curtains from those he found for sale that would fit his car. Yes, there are reproductions around that will not fit an original condition set of doors.

[A98Coupe]

A-snake,

Thanks for the reply, your measurement datum now makes complete sense and a good starting point for rough location of the rear studs on my 427. I'll wait to see if Jim is successful in making some patterns and then I should be sorted.
Thanks again
Stuart

[DMXF]

Dan - I agree that most of the variations in these cars today are from what was done to the cars after they left Shelby American. It's standard procedure for a manufacturer to use fixturing, etc to make cars uniform. However, between tops and tonnaus, I have a number of originals (and you and I both know how to tell originals) and some will fit my car and others won't. Yes, I know when these cars were new the tops/tonnaus were also sold as service replacements which probably required installation of the lift a dot plates, which could have been put in different locations. But that can also be viewed as a convenient excuse when no proof exists these particular tops/tonnaus came to be that way. Also, as mentioned before I have heard from at least a couple of others over the years that they have seen slight differences. Variations do exist in these cars. Just look at the example of our friend who recently restored his small block car (never wrecked) to extreme, exactling standards who couldn't find a side curtain to fit one side of his car among several he had, requiring in the end he modify one. One of these days I will put the studs back in the original holes in the body for the other car here and check the tops/tonnaus on that.

[DanEC]

Originally Posted by Dan Case

Somebody asked about the ferrules in doors for side curtains. I can show you the pattern in CSX2310. I did this sketch for a CSX24XX car owner last year. The center line is for the holes and not the top of the door. Measurements were just done with a tape measure. The information was good enough for him to pick a set of curtains from those he found for sale that would fit his car. Yes, there are reproductions around that will not fit an original condition set of doors.

This is helpful and I'm going to check it out on my ERA body to see how it matches. Unfortunately my main problem is that the rear and middle ferrule holes appear to have been drilled too far to the outside on one door compared to the other door.

As a simple alignment check - does the rear most ferrule fall in general alignment (longitudnally) with the first lift-a-dot stud on the rear fender?

Thanks

Dan

[1985 CCX]

Jim (A-Snake)

Thanks for all your time, it will allow me to get fairly close on my 289 build. Your sharing is 100% appreciated!

Thanks

[ERA Chas]

Originally Posted by Dan Case

Not proof on every car for sure but I have tried various original covers, tops, and side curtain sets on CSX2310 from chassis CSX2259 up to CSX3298 and they all fit just exactly the same. Several owners that I know of have tried several tops and covers each on their cars, usually making upgrades from poor condition to better condition ones. Other than the difference in middle snaps between Cobras and 427 Cobras fitments I have seen or been told about have been very consistent BUT these involve parts and cars that have never been seriously damaged or modified or had their skins removed from where AC Cars put them.

Dan,
Thanks for your evidence about these stud locations. As I said earlier, I am quite surprised that AC took such pains to get these locations consistent. We have seen much evidence that their panel guys had difficulty getting the body locations consistent, left to right and front to rear. This despite hammering aluminum against a wooden buck. The joining of the panels being the critical part.

Dcmgt's evidence about the side curtain fitment on an unmodified car is quite telling.

[A-Snake]

Originally Posted by Dcmgt

Dan - I agree that most of the variations in these cars today are from what was done to the cars after they left Shelby American. It's standard procedure for a manufacturer to use fixturing, etc to make cars uniform. However, between tops and tonnaus, I have a number of originals (and you and I both know how to tell originals) and some will fit my car and others won't. Yes, I know when these cars were new the tops/tonnaus were also sold as service replacements which probably required installation of the lift a dot plates, which could have been put in different locations. But that can also be viewed as a convenient excuse when no proof exists these particular tops/tonnaus came to be that way. Also, as mentioned before I have heard from at least a couple of others over the years that they have seen slight differences. Variations do exist in these cars. Just look at the example of our friend who recently restored his small block car (never wrecked) to extreme, exactling standards who couldn't find a side curtain to fit one side of his car among several he had, requiring in the end he modify one. One of these days I will put the studs back in the original holes in the body for the other car here and check the tops/tonnaus on that.

Mike, I will add one more element that can affect the fit. Shinkage. I had to have a new tonneau made about 5 years ago because the tonneau that came with my car in 1986 (and fit for several more years) had finally shrunk from non use. Even leaving the old tonneau in the sun on a hot summer day would not relax it enough to again fit the car. The first studs to no longer fit were the outboard studs on the rear cowl.