C1 Aux Hardtops

[Bill B.]

Currently, repairing and restoring my 59-60 style top. In the process of purchasing repair items, I have acquired a collection of other year style trim and assemblies because they were improperly listed by sellers or I just wanted the items so that I could compare changes made during the 56-60 timeframe. Consequently, now I am interested in all the 56-62 style tops. At the moment, I would like to know the following:

How was the 56 aux top narrow front header secured to the fiberglass roof panel?

What are the 56 narrow front header and roof panel part numbers?

The 56 side drip rails had a sharp top edge vs a later smooth/crimped top edge. Was this sharp edge side drip rail only used on the 56 or was it carried into 57 production and used with the wide exterior front header trim?

[Bill B.]

Re: C1 Aux Hardtops

The response has been simply overwhelming but I note that there are viewers. So, how bout do you know how many different side drip rails there are and can you tell the differences:

#1 - Early sharp top edge rail which has an extended tail to cover the rear "Y-clip" molding.

#2 - Similiar to #1 except has a smooth/crimped top edge, extended tail for the "Y-clip" molding, and front header stainless area contour a "little more" pronounced.

#3 - Looks just like #2 except rear tail is shortened due to "Y-clip" molding elimination and front stainless contour same as #2.

#4 - Looks very, very similar to #3 except rear tail is about 1/2" shorter.

Is the usage 56, 57-58(#6500), 58(#6500)-60, and 61-62? And, what are the part number for these assemblies?

[Rod K.]

Re: C1 Aux Hardtops

I have an early '57 top (Oct '56 dated glass) which has the sharp edged drip rails.

[Bill B.]

Re: C1 Aux Hardtops

Rod, thanks as I am looking for this type of info. From what I have read, I understand that maybe the first 100 or so 57 cars could have come with the narrow front header as on the 56 and possibly the last few 56's could have come with the newer wide 2" stainless header trim. Although yours has the sharp edge and is very early production, I assume your top has the wide header trim too?

[Gary C.]

Re: C1 Aux Hardtops

Bill,

Chill it's the holiday's. That could be a lot of research to assemble all the C1 Hard Top running changes.

Below are the '57 AIM hardtop sheets. Hope this helps.

IIRC '56-8 hard tops are the same with the exception of '56 and some early '57 (possibly) having the small front header trim.

As example the Hard Top side window 3729393 channel assembly is in P&A books Group # 11.005 1961 P&A shows that number changed to 3757795 for the 1959-61 Hard Tops.

You'll have to research the Judging Reference Manuals and Part Numbers in the AIM's and P&A's to find the differences.

Gary
....

[Bill B.]

Re: C1 Aux Hardtops

I am hoping that many viewers share the same interest as I do--especially if you are not sure of what top you really have, are trying to buy/sell a top, are trying to buy/sell parts on Ebay/Craig's List, or are doing a DIY restoration. I do have the 56/57 and 58 AIMs, Noland's book, and the 58-60 TIM/JG. In fact, I don't agree with the Late 58 top description in this guide and I owe Tim Mickey a reply if I can ever validate my findings.

Gary is very correct. You need many documents and someone has probably already researched this subject many times over. But, I sure cannot find it. Until somebody makes this easy for me, I am going to meander along and solve it for me and hopefully for some other folks just like me. In the end, I should have a good compliation of info, pictures and detailed desriptions for these tops--to SHARE!

Copies of the 59, 60, 61, 62 RPO 419 AIM pages and extracts of the other year TIM/JGs pertaining to the aux top would really help me in this effort.

[Gary C.]

Re: C1 Aux Hardtops

Bill,

Rev. Mike did an article on C1 hardtop differences in the Restorer Spring 1978 issue.

Gary
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[Bill B.]

Re: C1 Aux Hardtops

Gary, as always you are most helpful. Unfortunately, I don't think I want your advice anymore. You advised me to chill and referenced that Roman Numeral Two book or manual (IIRC). So, I decided this morning to chill back about 10:00, got a cold beer and thought I would search the net to see how I could buy one of those IIRC parts books in my aux hardtop quest for perfection. Took a big gulp about the same time as my search query ended for "IIRC"---up pops "IF I REMEMBER CORRECTLY"--well, beer went down the wrong pipe, back out my nose, sprayed the Christmas Tree and laptop with what was still in my mouth, coughed and laughed for at least 15-minutes, and then I tried to look intelligent for my family. Thanks!

I got some of my parts from Mike and knew that he had written a restorer article on the hardtop at some point in time. Would really like to read it but I hate to spend $150.00 for the DVD right now--call me cheap. Although I did not know Ted Kolitus (sp), he had a wealth of hardtop knowledge that is gone. I have talked a little with his son Matt. Two main folks that come to mind for me, Mike Ernst on the identification side and John Hincely for in-plant insights. I just don't want to bother them right now. Gary--Thanks

[Gary C.]

Re: C1 Aux Hardtops

Bill,

Didn't mean to make you waste a good beverage. Sorry about that. I have CRS so I use the IIRC quite often.

Since you made me smile today, I copied the text from Rev Mike's hardtop article for you. Hope this makes amends.

Gary
....

1956-1962 HARDTOP
IDENTIFICATION
By Michael Ernst

There is nothing more prominent or in plainer view on a Corvette of any year than the top. Nothing is more obvious, then, than an incorrect hardtop. Although tops made any year from 1956 through 1960 will
fit any car made '56-'60, that doesn't mean they are correct. All '56 thru '60 hardtop headliners corresponded in color and vinyl pattern to the car's interior, so that rules out most
interchanges. Also, all hardtops with original windows have date stampings in each window, which clearly identify them
as a top manufactured in a certain month and year for a certain model year.

1956 was the first year the hardtops were offered for production by Chevrolet, and the '56 top is characterized by a thin aluminum strip on the header portion of the
hardtop, above the windshield. Sometime during the 1956 model run, it is believed, and running through the '62 model, a three-piece stainless steel moulding was added to the front header for assembly and appearance purposes. Both '56 and '57 tops featured a waffle-pattern headliner.

Those two tops, as well as '58, '59, and '60 fastened to the car in a similar manner. Each had two latches fastening it to the windshield, and had three brackets along the rear bow, through which bolts passed to fasten it to the rear deck soft top cover of the car.

The 1958 Corvette hardtop is in a class by itself. It was the only model to use the pebble-grain, or "Chatham" grain vinyl, on all the upholstery material including the hardtop
headliner. The exterior appearance of the '58 top was a carry-over from the '56-'57, as those three tops featured a three-piece molding around the rear bow. One piece
extended on each side from the front to the rear of the side window, where they were joined by a single "long" molding extending all the way around the back. Over each joint was fastened an inverted "T"shaped molding to bridge the gaps.

The '59 and '60 hardtops then featured a one-piece molding, extending around the entire rear bow. Those two tops use a headliner vinyl which matches that of the interior in grain and color.

The 1961 Corvette hardtop shows numerous changes. The body received a rear "wind split" running down the car's centerline, so the hardtop for '61 and '62 was redesigned to fit. Even disregarding that change, the '61-'62 tops will not interchange with earlier tops because the rear deck was designed with a flatter contour, less rounded than the earlier cars.

Mounting was also changed in '61-62, with brackets on the rear bow located right next to each door, the center bracket removed, and the two rear brackets moved several inches toward the rear centerline. All '61 and '62 hardtops used only a white headliner, and are interchangeable except for the date stampings in the plexiglas windows.

If you are considering the purchase of a hardtop, there are certain items to be aware of. Hardtops have a tendency to lose the center clip front molding. Many '56-'60 tops, because of the rear center clip,often have a cracked back window in the small area around that center mount. And the '61-'62 tops are often missing the two brackets
adjacent to the doors.

Replacement rear windows are still available from GMPD, as are front latches, and rear hold-down bolts. Side windows and headliners are available from reproduction sources. But, rear brackets and interior and exterior stainless moldings are nearly impossible to find, and are priced accordingly if available.

[Rod K.]

Re: C1 Aux Hardtops

Yes, it does have the wide header trim. Can't testify as to the actual date of mfg as I obtained it separately from the car.

[Bill B.]

Re: C1 Aux Hardtops

Okay, I took Gary's advice and made a fool out of myself but I do forgive him, kinda. I have studied the early 56/57/58/59 AIM drawings. I have read Noland's book hundreds of times and I love that book. I have read my 58-60 TIM/JG over and over. I have gone through archive searches and read questions and responses, some good and some not so good. I have handled my small collection of parts by physically inspecting and measuring and comparing. I have reviewed vendor catalogs and read many EBay/Craigl's List listings. Over the past year several folks have emailed me photo details of their tops. I have asked many questions on this subject and unfortunately many times I have not gotten an answer or reply-not complaining. The Glassworks folks have sent some small hardware parts and I have talked with Matt a couple times. And, all need to know that I have a very high regard for the NCRS and our members even if I don't participate very much. In the end, I just like to do things correctly, the first time. I also know that if I am having a problem with something, that usually means that I am not alone or the only one.

For me, I have a late production 58 (serial around 7400) and I bought a damaged 1960 top which had fallen off a car in tow. The rear main stainless channel was severely bent and the right side drip rail was damaged beyond repair. So, I sent my 1-piece stainless channel to Glassworks for straighting and started my search for a new drip rail. I also determined by reading my 58-60 TIM/JG that this 60 top actually had all the right "bones" to be correct for a late 1958 car (after serial number 6400). That is how this all started and it just kept getting more and more complex--I know, go to the NCRS technical discussion board for help.

I am posting this as the introduction for my situation. I will follow with another post in the next couple of hours by detailing what I think a 56, 57, and 58 (prior to serial #6400) top looks like--real details. And, then later I will do the same for tops from 58 (after serial #6400) to 1960. It is really a tricky issue to me.

[Gary C.]

Re: C1 Aux Hardtops

Bill,

1957 Hardtop change - Interior side trim - approximately VIN 3700 added 3 retaining screws. Previously the Interior side trim was clipped on.

1956 Hardtop rear windows use the following date code “7 6” (July 1956). Starting with 1957 year model the rear window used a two digit year date code “11 56” (November 1956).

1956 and 1957 Hardtop side windows are date coded with month and single digit year date code (example: “7 6” would indicate July, 1956) for both 1956 and 1957 model year hardtop.

Gary
....

[Bill B.]

Re: C1 Aux Hardtops

I am at my lake house but once I get back to our Galveston home I will have access to my scanner, camera and other pictures. I know pictures would really help here. My effort is not to create a judging guide! I just want all of us to be able to quickly bracket a period when a top would most likely be correct and then be able to better understand its total configuration. If an issue falls in the unknown/fringe/transitional change period, then pursue additional clarification.

Starting with the 1956 top, let me first say that I have never really seen or touched one except for the pictures in Noland's book on pages 111 and 112. The 56/57 AIM is of no help here as the RPO 419 drawings were revised 7-31-56 for 1957 production. And, I have no idea what the 56-57 TIM/JG states. I suspect a couple of 56 tops could have crept into very, very early 57 production? With this said, here is my take on the 1956 top.

The 56 top is one of the easiest to identify. Essentially, if you see a narrow (approx 1") front header and a rear "Y" stainless escutcheon, then all odds are that you have properly identified it. Unique to this top are the fiberglass roof panel, the front aluminum header, the attachment of these two items, and the side drip rail assemblies. I am hoping that someone will post how this roof panel was secured at the front. To me, I would guess that it was bonded to the header or secured from the underside with screws or--I just don't know? Regardless, the AIM isn't going to give you any help pertaining to these items. Noland's book also mentions that some headers were painted and some not.

As Mike Ernst stated in his article, "sometime" in 56 the front header was changed to a "newer" wide style with 3-piece stainless trim. When this occurred, the fiberglass roof panel also had to change. This "newer" style header and roof panel is what the 56/57 AIM pages illustrate and nothing concrete about 56 tops. Additionally, the side drip rail assembly is of what I will call a "1st Design" rail. It was screwed to the header and roof panel sides and riveted to the rear window frame structure. This first design rail also had a "sharp" top edge along the profile. The rail rear tail is longer than 58L to 60 style rails so that the profile edge extended down and over the "Y" clip. The front of the rail has a very definite contour stamping which stops about 1" back and then is flat to the end where it attaches to the header.

Of note in the AIM, is the part number change for the rear center hold down bracket on 8-20-56. It was changed from 3726881 to 3740214. I know that the newer bracket is chrome plated cast with three lower rivet attachment holes to the main frame channel and two upper rivet holes which secure rear window glass at the center. I have no information on what the original 3726881 bracket looked like on a 56 top. To me, the remaining 56 structure as revised for 57 is probably the same as shown in the AIM. This remaining structure such as the channels, brackets, main frame, and different drip rails will be addressed in the 57 to 58L (serial #6400) portion to follow.

For now, I am not going to detail items such as the front latches, headliner, glass, most interior/exterior stainless trim, weatherstrip--will save that for last because I think it easiest to deal with. If I have something wrong here, then you need to get me corrected. If you can clarify better, do that too. Will follow this post with the 57-58L (approx serial #6400) tops.

[Bill B.]

Re: C1 Aux Hardtops

THE 57 to 58 (approx serial #6400) HARDTOP. At 58 (#6400) a significant change occured. From 56 to 58 (#6400) the "Y" stainless rear clip was used, the rear lower exterior stainless window trim consisted of a long curved center section and two straight side sections, and the rear lower main stainless weatherstrip channel was a 3-piece spotwelded stainless channel assembly. After 58 (#6400) the "Y" clip was eliminated, the rear lower exterior stainless window trim consisted of two long curved sections and they were covered at the rear center by a small stainless center clip, and the rear lower main stainless weatherstrip channel was a 1-piece stainless channel from side-to-side. Details about the 58 (#6400) to 60 will be described in a later post.

It appears to me that there are three possible top variants for 57 cars and 58 cars prior to #6400. The 1st Variant is that possibly a handfull of early 57 cars came equipped a carryover 56 narrow header "sharp" edge drip rail with "Y" clip style top. I don't know this for sure! The 2d Variant is 57 tops came configured with the "newer" wide style header and front 3-piece stainless trim and a "sharp" edge drip rail with "Y" clip. The 3d Variant is identical to the 2d Variant except the drip rail edge is "smooth/crimped over". As I mentioned above about the 56 top, I couldn't find alot of definitive source information but I think I am close in its details. As for 57 production, the AIM is very helpful but does not provide any kind of change date for the side drip rail changing from "sharp" to "smooth/crimped over". The 58 AIM isn't helpful on this issue either. My study of the 57 AIM indicates that the drip rail shown is the newer "smooth/crimped over" rail (3726387/3726388). Therefore, the previous "sharp" edge appeared in 56 AIM pages that were removed prior to 7-31-56 and I do not know the part number for it.

Hopefully you are following all this "sharp" and "smooth" edge stuff about the drip rails. The reason it is important is that the 58-60 TIM/JG states "The stainless rain gutter for early 58 is a single (sharp edge) variety". In my stash of parts I happen to own an example of the very early "sharp" edge and a "smooth" rail. Both were used for tops that needed the extended rear tail for the "Y" clip. So, I think the TIM/JG may be incorrect. The two rails are nearly identical and completely interchangeable except for the top edge. To complicate matters further, a review of the 58 AIM shows that the side window view was redrawn on 6-23-58 and the drip rail part numbers are 3757791/3757792--I am almost positive these are drip rails for the #6400 to 60 redesign which eliminated the "Y" clip and shortened the rail rear tail. The 57 AIM showed the change from "sharp" to "smooth" edge rails but the change may not have immediately taken place as evidenced by Rod's very early "sharp" edge wide header style top. In the absence of something definitive, I have to believe the change fully occured in early 57 and remained in effect till 58 #6400. So, should the TIM/JG read "The stainless rain gutter for early 58 until approx serial #6400 is a "smooth/crimped over" top edge style."And, how does one know when a 57 top could or should have either "sharp" or "smooth" drip rails? How have we judged this in the past or present?

If you couldn't follow this, wait till I try to explain the after 58 (#6400) to 60 changes.

[Bill B.]

Re: C1 Aux Hardtops

Left photo: front profile on a "sharp" top edge drip rail used with the 56 style narrow header and also found on 57 tops with the wide header.
Middle photo: front profile found on the 57 to 58 (serial #6400) which has a "smooth/crimped over" drip rail top edge. the same profile is found on the 58 (#6400) to 60 drip rail which is also "smooth/crimped over".
Right photo: front profile found on the 61-62 drip rail. it is a "smooth/crimped over" top edge.

Drip Rail Frt Contour.gif