Spoiler availability

[MO]

The Shelby Daytona Coupe used one in 1964. However, I believe we are 'stretching' it here. The Cobra and Corvair Stinger were race cars, not production cars.
Here is a picture for a reference.

I agree, racecars should not be considered in this dialogue.
Good call on the 67 Shelby's Jon; I had forgotten about them.

[MO]

here is an 1967 ad for a Yenko Stomer with spoiler

Joe, That's a good comparison for height. The Stinger looks to have a curve that you can see in the stripe as compared to the flat look on the press car.

[369]

These came from the other thread.....so how did the “tall” spoiler come to be? Just a custom piece to do a job or was it something being manufactured at the time?

[crossboss]

The top photo is very interesting. It appears to be what some would call a 'duck tail spoiler'. Its very effective on producing down force. It appears to have a similar design as the '67 Shelby Mustangs. The other photo is of course very close to the production spoilers. Wonder how the SCCA/FIA ruled on the duck tail's legality? Thanks for posting.

[MO]

Jon, is it known which shape was used for the Chevrolet blueprint? I would presume the shorter style.

[KurtS]

The blueprint from GM would be the same as the production part, same part #. Surprisingly, the number never changed through all of 67 and 68.

[JoeC]

Yenko used two local fiberglass companies to make parts for him. One company's main business was fiberglass bath tubs and shower stalls.

Yenko had fiberglass hoods, deck lids, seats, spoilers and other parts made to his design

Yenko, and probably others back in the day, would use their racing buddies to get parts and services as many racers were business owners and raced more as a hobby.

I have a set of prototype fiberglass side pipe covers Yenko had made for 67-69 Camaros. They are too thin and have cracking so didn't go into production.  here is the receipt

[MO]

Cool piece Joe!

[MO]

The blueprint from GM would be the same as the production part, same part #. Surprisingly, the number never changed through all of 67 and 68.

Thanks for confirming Kurt.

[msbrunner@ucdavis.edu]

Interesting to see the Car Life spoiler results, suggesting front but no rear spoiler was best overall for a road car. Donohue says in The Unfair Advantage that when they finally brought their '67 to Milford, the GM numbers showed their spoilered car at 100 mph to generate 50 lbs lift front and 100 lbs downforce rear. Rear matches the Car Life '69 street car downforce but front is vastly better on the race car, which I would bet is all to do with the low ride height of the race car. Fun stuff!

[msbrunner@ucdavis.edu]

I should say, lower ride height plus stiffer springs on the race car to keep ride height more constant through the aero load. And while this is ultimately a trans-am series development, I hadn't put together until now how a drag-race suspension config not only helps with weight transfer to the rear but also reduces front splitter performance as the front lifts which would actually increase straight-line stability...

[KurtS]

Good point on the difference in spoiler performance between production cars and race cars.

[MO]

I was going through the AIM for something else and looked in UPC Z28 as well. There are a couple things that strike me as interesting about this drawing and it's relationship to this thread:

1. The first revision is dated 12/5/66 and notes RPO D80. Given that it already had an RPO assigned, could that mean that spoilers were already available?
    Or is it an indication that it is intended to be available? I can't imagine it being available at that time or they wouldn't have been handing out blueprints
    on how to build them. Is there an early parts book or option list/catalog that might have anything on it and a date to help narrow it down?

2. The second revision is dated 2/16/66 (which I'm sure is a typo, but not sure if it should be 12/16/66 or 2/16/67). It indicates how to paint the stripe on
    the spoiler. It's interesting to note that the stripe was painted only to the bottom edge of the spoiler. It doesn't state this, but it could also be indicating no
    paint on the lip of the trunk lid, as spoilers were painted when factory available. 

[KurtS]

1. The first revision is dated 12/5/66 and notes RPO D80. Given that it already had an RPO assigned, could that mean that spoilers were already available?

No, that indicates the engineering drawings and paperwork were done.