Front Valance Air Dam on 1969

[Keith M.]

I came across the existence of these whilst perusing a vendor catalog. What I am referring to is the air dam that attaches under the front bumper valance. Purpose of it is to augment air flow to improve cooling primariily. I believe these were kept in the black? Anywho...question is whether or not all 1969s had these? or maybe just big blocks? Searching some internet forums has come up with evidence that all 1969s had them. Yet my review of the AIM could not find this part specified. Just wanting to verify this part was necessary to be correct for my L46...cuz if it had one it is LOOONNG gone..
Thanks!

[Arland D.]

Re: Front Valance Air Dam on 1969

Keith,

My 69 350 / 350 Cortez silver convertible had the black air dam attached to the front valance when new.

[Keith M.]

Re: Front Valance Air Dam on 1969

Thanks Armand!! Not that it matters for this topic (I don't think) but do you know your car's birthday? Reason I ask is my 350/350 4spd was born Cortez Silver but someone along the way painted it Cliche Corvette Red. She will get her original color back at the tail end of the restoration as well as black convertible top replacing the current very tired white one. Mine was born late October.

[Terry M.]

Re: Front Valance Air Dam on 1969

Keith
See UPC 11-13, Sheet A3 for the Radiator Grille Lower Panel Extension (ain't that a mouthful! That's why it is commonly called a spoiler or air dam.) that all 1969 Corvettes had.

[Joe L.]

Re: Front Valance Air Dam on 1969

I came across the existence of these whilst perusing a vendor catalog. What I am referring to is the air dam that attaches under the front bumper valance. Purpose of it is to augment air flow to improve cooling primariily. I believe these were kept in the black? Anywho...question is whether or not all 1969s had these? or maybe just big blocks? Searching some internet forums has come up with evidence that all 1969s had them. Yet my review of the AIM could not find this part specified. Just wanting to verify this part was necessary to be correct for my L46...cuz if it had one it is LOOONNG gone..
Thanks!

Keith------

ALL 1969's were originally equipped with the "air dam" (an extension in GM-speak) you describe. The extension was GM #3932933 and was used for all of 1968 and 1969. For 1970-72 a very similar extension, GM #3974013, was used. The 3974013 became the SERVICE extension for 1968-69 when the 3932933 was discontinued in May, 1970.

Both of the above were black plastic (polypropylene, I believe) and were NEVER originally painted on any 1968-72.

[Keith M.]

Re: Front Valance Air Dam on 1969

Thanks Terry and Joe. I bow in reverence to your extensive knowledge and willing assistance.

A good example with the AIM of...why the heck did they put it in that section? I get that it provides cooling function for the radiator...but would have thought it be in the "bumper" section. In any event, thanks again. This is, I think, component number 483 that was removed from my car...unreal how previous owners just said...nah, we don't need that...with so many aspects of my car. Heck..there WERE four bolts but can't find the other two so meh roll with just the two.

With the air dam...I kinda get it. Likely there were few 69s that by the early 70s did NOT have this spoiler scraped up if not entirely trashed by the local driveway, curb, shopping center parking block or what have you. As this restore progresses I begin to feel I will ultimately be putting back half of what came with it from the factory!!

[Terry M.]

Re: Front Valance Air Dam on 1969

Thanks Terry and Joe. I bow in reverence to your extensive knowledge and willing assistance.

A good example with the AIM of...why the heck did they put it in that section? I get that it provides cooling function for the radiator...but would have thought it be in the "bumper" section. In any event, thanks again. This is, I think, component number 483 that was removed from my car...unreal how previous owners just said...nah, we don't need that...with so many aspects of my car. Heck..there WERE four bolts but can't find the other two so meh roll with just the two.

With the air dam...I kinda get it. Likely there were few 69s that by the early 70s did NOT have this spoiler scraped up if not entirely trashed by the local driveway, curb, shopping center parking block or what have you. As this restore progresses I begin to feel I will ultimately be putting back half of what came with it from the factory!!

Keith
The air dam (extension) is useful, and in some cases necessary, for engine cooling. If your car is to be driven much you will want to have it in place. If your goal does not involve NCRS judging a bolt and some washers from the hardware store will work well. Stainless fasteners work wonders and will last longer than either of us and our children.

If your ultimate goal is judging then those bolts and the spoiler are a whole other matter. Just as a note: for 1969 the factory installed those bolts with the nut facing forward. You or others having their chrome bumper C3 judged might want to see the TIM&JG for more information on this. See the 6th Edition of the 1968-69 TIM&JG, Page 208, Fig CH 3.6 to 3.9 as well as the text on this subject on Page 208 & 209. If judging this item there is more to it than meets the eye. The fact that the Chassis team judges this also makes the information lurking in an unexpected location.

[Gary B.]

Re: Front Valance Air Dam on 1969

As Paul Harvey would have said... And now the rest of the story...

Early 1968's did not have a lower extension (spoiler) installed from the factory. In the Assembly Instruction Manual (AIM) UPC 11-13, Sht. A 2.5 which was drawn 11-28-67, Released 11-30-67 showing the lower spoiler and part number and the bolts and nuts securing it to the lower valance.

Chevrolet Technical Service Bulletin 68-T-9 dated Dec. 27, 1967 (somebody was working between the holidays back then) discusses the cooling issues with 427 equipped 68 Corvettes and the changes required to improve cooling.. It says that holes under front valance and a new extension was added at car Serial Number S400720. Lower valance part number is listed as 3932933, as Joe has listed above. The last car built in September 1967 was SN 950. The TSB has a template attached for the cutout in the lower valance panel. I've seen several early original unrestored 68's without the cutouts and lower spoiler.

Gary Bosselman

[Keith M.]

Re: Front Valance Air Dam on 1969

Keith
The air dam (extension) is useful, and in some cases necessary, for engine cooling. If your car is to be driven much you will want to have it in place. If your goal does not involve NCRS judging a bolt and some washers from the hardware store will work well. Stainless fasteners work wonders and will last longer than either of us and our children.

If your ultimate goal is judging then those bolts and the spoiler are a whole other matter. Just as a note: for 1969 the factory installed those bolts with the nut facing forward. You or others having their chrome bumper C3 judged might want to see the TIM&JG for more information on this. See the 6th Edition of the 1968-69 TIM&JG, Page 208, Fig CH 3.6 to 3.9 as well as the text on this subject on Page 208 & 209. If judging this item there is more to it than meets the eye. The fact that the Chassis team judges this also makes the information lurking in an unexpected location.

Hi Terry,
I am in the early stages of this restore, it being my first, though I have owned the car since 1997 and am at least the third owner. My "goal" at this point is probably best stated as making it much more close to original than it is now. An easy threshold given how much this car was abused. I use NCRS and judging information as a guide. I care about correct part numbers, date codes, appearances, materials, etc....recognizing that some things are unobtanium and many/most have a cost/benefit threshold. While I do not ever envision this car an award winner I cannot say I will never have it judged and if so..would be, moreso than to obtain an award, to help me improve it closer to originality. Said judging is at least two years away if not more. I am enjoying the process but still in the stage that everything I touch becomes yet another rabbit hole.

Coming back to the air dam...for sure I want to put one in and in as original set up as possible. I have my eye on air dam and hardware (MFC headmark) from Paragon...including the bumperette brackets which are also missing. Will that not do the trick for judging? I understand and value the cooling benefit...that said...the car never ran problematically hot before it went to sleep in 2001 only to awaken last year and begin the restore. Thanks for pointing my to the TIM&JG info. I continue to be surprised at content covered in there.

[Terry M.]

Re: Front Valance Air Dam on 1969

Hi Terry,
I am in the early stages of this restore, it being my first, though I have owned the car since 1997 and am at least the third owner. My "goal" at this point is probably best stated as making it much more close to original than it is now. An easy threshold given how much this car was abused. I use NCRS and judging information as a guide. I care about correct part numbers, date codes, appearances, materials, etc....recognizing that some things are unobtanium and many/most have a cost/benefit threshold. While I do not ever envision this car an award winner I cannot say I will never have it judged and if so..would be, moreso than to obtain an award, to help me improve it closer to originality. Said judging is at least two years away if not more. I am enjoying the process but still in the stage that everything I touch becomes yet another rabbit hole.

Coming back to the air dam...for sure I want to put one in and in as original set up as possible. I have my eye on air dam and hardware (MFC headmark) from Paragon...including the bumperette brackets which are also missing. Will that not do the trick for judging? I understand and value the cooling benefit...that said...the car never ran problematically hot before it went to sleep in 2001 only to awaken last year and begin the restore. Thanks for pointing my to the TIM&JG info. I continue to be surprised at content covered in there.

Keith
Since you have some time on your hands before rolling your 1969 out potentially for judging or driving why not put those bolts on your list for original search. I can't tell you how accurate the reproductions are. Someone else here might. My days of judging chassis are long in the rear view mirror.

One thing about fastener headmarks one should keep in mind. It is unlikely that only one headmark was used in any location on the car. One headmark would mean that there was only one supplier of that fastener. For some (only a few) very unusual fasteners there was only one supplier, but in general Chevrolet didn't want to be "stuck" with one supplier in the event something happened to that source to prevent delivery of the product. So don't concentrate on headmaarks. Look instead for configuration first, then at finish. The last thing to concern yourself with is the headmark. That said, the folks who specialize in judging a given area of the car know, or think they know, those headmarks that were contemporaneous with the build of the cars. They will make a note if they see what they think is a more modern headmark. If they are properly using CDCIF in judging this situation if all four bolts were stainless screws instead of bolts they would be hard pressed to justify a single point deduction. But I know some who would try.

Remember Judging is a game whose goal should be improving the car toward Typical Factory Production. Note the word TYPICAL. It is not a contest of wills between the judge and the owner.

[Richard K.]

Re: Front Valance Air Dam on 1969

Keith,
Back in the '70's, my buddy and I were drag racing at 3a.m. on a long stretch of lonely road. It was my '69 L46 vs. his '73 L82. As we reached 100-something, and we weren't backing-off, my front end began to lift. The lift felt to me like a jet liner going down the runway and getting ready to lift the front wheel(s). Ironic, because my buddy said that I passed him "like a jet taking off". I immediately backed off when I felt lift as it scared the crap out of me. Next morning, I began to snoop around the front of the car and noticed that I didn't have an air dam like other Corvettes did. So, I immediately went out and bought, and installed the factory air dam (extension) since the mounting holes were there.
I don't believe that GM ever officially said that early C3's had a lift problem, but it felt like mine did. Maybe they didn't want to make that info public so that they could avoid any potential lawsuits.
I've never driven my L46 that fast again, and probably never will. Was the lift my imagination? I don't want to test the car to find out.
Rich

[Keith M.]

Re: Front Valance Air Dam on 1969

Keith
Since you have some time on your hands before rolling your 1969 out potentially for judging or driving why not put those bolts on your list for original search. I can't tell you how accurate the reproductions are. Someone else here might. My days of judging chassis are long in the rear view mirror.

One thing about fastener headmarks one should keep in mind. It is unlikely that only one headmark was used in any location on the car. One headmark would mean that there was only one supplier of that fastener. For some (only a few) very unusual fasteners there was only one supplier, but in general Chevrolet didn't want to be "stuck" with one supplier in the event something happened to that source to prevent delivery of the product. So don't concentrate on headmaarks. Look instead for configuration first, then at finish. The last thing to concern yourself with is the headmark. That said, the folks who specialize in judging a given area of the car know, or think they know, those headmarks that were contemporaneous with the build of the cars. They will make a note if they see what they think is a more modern headmark. If they are properly using CDCIF in judging this situation if all four bolts were stainless screws instead of bolts they would be hard pressed to justify a single point deduction. But I know some who would try.

Remember Judging is a game whose goal should be improving the car toward Typical Factory Production. Note the word TYPICAL. It is not a contest of wills between the judge and the owner.

Hi Terry,
Thanks for the input and advice. Allow me to clarify my view/plans for judging and my restoration philosophy in its current state. My approach, as I had said, is to restore my car to be much more "correct" in terms of how it "most likely" came from the factory. Your comment around TYPICAL resonates with me. I am not chasing awards or points. I view NCRS judging/judges as advisors to me in my restoration efforts. It is my call on how I want to deal with each situation recognizing the associated trade offs. I have no intent ever to get into a "contest of wills" with a judge. I simply want to tap their knowledge and experience as a guide for me. So I guess for me they are more advisors and/or assessors than "judges". I would go so far to say in the extreme that there may be cases where something did in fact come from the factory in a state that no one has ever observed before. Unlikely but entirely possible. Lots of funky things can happen on a factory assembly floor as well as a manufacturing plant...especially circa late 1960s, and especially in supply chain disruption caused by GM strike in 1969. Said strike pushed production of the 1969 model year much further in the calendar year than usual and start of 1970 builds from the typical Aug 1969 to Jan 1970. It is entirely possible any parts that changed somehow 1969 to 1970 were on the floor in late Oct 1969 when my car was assembled. Other minor MY changes to 1970 parts/assembly/configuration COULD also have been applied to a late Oct 1969 build. I don't think anyone can say with absolute certainty that never happened. Lastly, I am doing a driving restoration. Being in my early 60s I do not want to forego for even one summer my opportunity to enjoy use of my car. This does introduce some constraints. If I start chasing EVERYTHING in the name of correctness in the eyes of NCRS or a judge...I will go to my grave never driving this car again. With this air dam example, it'll be...get the part and harware from Paragon, install, and move to the other billion things than need addressed. Another perspective...I bought this car in 1997 and enjoyed simply driving it for 3 years before mothballing it. All its seemingly infinite deficiencies of which I was unaware at the time did not detract from my enjoyment at the time. In short, I am doing this restore purely for the sake of preserving a piece of history that I admire very much and the immense satisfaction I gain from doing that, the vast majority of it with my own hands. So far, so good!

[Patrick H.]

Re: Front Valance Air Dam on 1969

With this air dam example, it'll be...get the part and harware from Paragon, install, and move to the other billion things than need addressed.

Just so you know, I do not believe anyone sells entirely correct hardware for this application.
All the parts should be black phosphate, and the bolts should not have the unthreaded portion on the tip that they all seem to have in the repro kits.