Correct tonneau stud pattern for 427 cobra

[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.

[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

[A-Snake]

Originally Posted by DanEC

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

No, the ferrule is inboard by perhaps 1/2" center to center.

[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.

[Dan Case]

Originally Posted by ERA Chas

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.

Fenders were made by one of several suppliers according to the many sources in the UK. Each panel shop no doubt made panels differently and AC had to make them work. Based on old factory images and comments by ex-works people all the body holes including things like demister slots were put near the end using templates. I would think it odd to have more than one template but I can see how hand held templates could get used with less than great care. So were there odd balls, I would imagine yes but I use to play with Boss 302 and 429 Mustangs and they have hand done operations that sometimes got off plan also. I work in a consumer appliance plant and we produce more than a million units a year. Are they all the same, no way, all production operations have "deviations" so don't get too hung up on finding occasional anomalies. When people ask what is typical or normal for cars I can tell them that but I can’t tell them every screw up that no doubt happened. I have worked on Cobras that had holes and the part that was supposed to be in it missing like a carter key hole that never got drilled or a throttle stop that never was installed. Anomalies yes, normal no. Learning what was typical is a totally different subject than covering every possibility that might have or did happened.

The danger in answering anybody’s inquiry in writing is that somebody will have an exception to toss out. I know, I do it too when somebody says such and such was ‘never’ done.

Regarding the ill fitting side curtain. If it is the person and car I am thinking of the confusion was he did not know that the side widow hung over the back end of the door and tucked inside the windshield frame in front. The person I worked with couldn’t understand how a curtain longer than the door could fit the door. I took a series of measurements and photos of CSX2310 and presto the side curtains he had that he thought too long were the correct ones. Case closed.