Shelby Guru Question - NACA Duct Hoods

[shelbymann1970]

Believe these are the ones we purchased

Those will still allow a hood to bow. When I stored my vert at a friend's garage for 6 months when I went to see it my hood was BOWED with those springs as I forgot to take them off. Took them off and the hood relaxed back down over time.

[FL SAAC]

Believe these are the ones we purchased

Those will still allow a hood to bow. When I stored my vert at a friend's garage for 6 months when I went to see it my hood was BOWED with those springs as I forgot to take them off. Took them off and the hood relaxed back down over time.

Good Lawd almighty I gots to take a them off B 4 it's to late !

[Bob Gaines]

Believe these are the ones we purchased

Unlike what Branda's description says those lighter tension springs were only used in 1967 production but that is beside the point. The light tension springs can be a good compromise between what was engineered and proper function to address the bow of the hood. Less tension equals less bow on a weak structure hood. Of course no tension means no bow but having no spring or putting a length of chain in place of the spring when the hood is up is a hassle (although the hood will never fall with the chain in place). Also the hoods were designed to stay up with the larger stock springs so when using the light tension springs it doesn't take much of a breeze etc, for the hood to fall. You have to keep a eye on them at a show so as not to have a hood slam down on someones head or hand. Fixing the inner structure so as to allow the use of the proper stock tension spring is the solution to make the hood perform as engineered but admittedly it is much more involved compared to any of the compromise fixes.

[FL SAAC]

Believe these are the ones we purchased

Unlike what Branda's description says those lighter tension springs were only used in 1967 production but that is beside the point. The light tension springs can be a good compromise between what was engineered and proper function to address the bow of the hood. Less tension equals less bow on a weak structure hood. Of course no tension means no bow but having no spring or putting a length of chain in place of the spring when the hood is up is a hassle (although the hood will never fall with the chain in place). Also the hoods were designed to stay up with the larger stock springs so when using the light tension springs it doesn't take much of a breeze etc, for the hood to fall. You have to keep a eye on them at a show so as not to have a hood slam down on someones head or hand. Fixing the inner structure so as to allow the use of the proper stock tension spring is the solution to make the hood perform as engineered but admittedly it is much more involved compared to any of the compromise fixes.

+ 1 I can attest to that,  once at a car show a fella was almost inside my engine compartment and boom that hood came down like a gator being fed chicken

[shelbymann1970]

Believe these are the ones we purchased

Unlike what Branda's description says those lighter tension springs were only used in 1967 production but that is beside the point. The light tension springs can be a good compromise between what was engineered and proper function to address the bow of the hood. Less tension equals less bow on a weak structure hood. Of course no tension means no bow but having no spring or putting a length of chain in place of the spring when the hood is up is a hassle (although the hood will never fall with the chain in place). Also the hoods were designed to stay up with the larger stock springs so when using the light tension springs it doesn't take much of a breeze etc, for the hood to fall. You have to keep a eye on them at a show so as not to have a hood slam down on someones head or hand. Fixing the inner structure so as to allow the use of the proper stock tension spring is the solution to make the hood perform as engineered but admittedly it is much more involved compared to any of the compromise fixes.

I have the perfect answer; I show my car with the hood closed. That is the natural state of the car. If someone wants to see the engine I'll lift the hood momentarily. Unless you have some "bling" engine you want to show off that is the center piece of your car I think the best way to views these cars are with the hood closed. Of course my opinion. I' next to a friend's 67 Vette and a friend's 69 B9. Both have their hoods open. I'm just showing I practice what I say.

[kansascarguy]

Check out my post in the "Services Offered" section. If you want that hood fixed permanently, . . . . . . . .

[SCJSTU]

on one of the 69 hoods I had in the past there was a really big bow in drivers side.....I laid towels down on both fenders......laid a 40lb bag of potting soil down on both sides of hood.....let car sit all day in 95 degree heat and now no bow......

[TA Coupe]

Putting weight on the hood in the hot sun or otherwise so to push it back into shape is not typically a long term solution. It will most likely bow again under the same heated conditions.The only sure fire permanent solution I am aware of is to notch and add small sections to the inner structure so as to add tension and compensate for the flex/bow.

Bob, you being a concours judge I find it hard to believe you would suggest such a thing.  Oh the horror of it 🙀😉

          Roy

[Bob Gaines]

Putting weight on the hood in the hot sun or otherwise so to push it back into shape is not typically a long term solution. It will most likely bow again under the same heated conditions.The only sure fire permanent solution I am aware of is to notch and add small sections to the inner structure so as to add tension and compensate for the flex/bow.

Bob, you being a concours judge I find it hard to believe you would suggest such a thing.  Oh the horror of it 🙀😉

          Roy

Roy, I know that was said all in fun but It should not be hard to believe that I would much rather see a hood that looks like it is supposed to from the factory rather then one with a horrible looking bow,the wrong springs ,or no springs. That factory look is the goal of any repair and the expectation in concours. How you get there is the challenge.  You can attain that goal by doing strategic surgery to the hood inner structure as has been talked about by myself and others . That process includes making the inner structure look like factory untouched when done. Just like any other fiberglass repair some are better at doing it then others. With that all said the other compromise fixes may be perfectly fine depending on the persons expectations . I am about helping maintain within reason and not always just concours perfect.  It is better to do what is best for you IMO.

[eric lipper]

Ok, now for my dumb question.  What is the process for removing the springs.  I am going to try taking mine off for a bit and seeing how that impacts my bow.

[richflorence]

I have always used a long wooden handle screw driver to remove the springs On mine. I run the shaft of the screw driver through the attaching loop of the spring, holding the handle in one hand and the shaft of the screw driver in the other. Mine have always come off easily using this method. I take them off over the winter, and this has allowed the hood to just relax back into it's normal contour. The car is 53 years old and unrestored, and I've never had any form of serious hood arch doing this.

[Bob Gaines]

Ok, now for my dumb question.  What is the process for removing the springs.  I am going to try taking mine off for a bit and seeing how that impacts my bow.

I use the space saver spare hold down hook that you should already have in your car. Have a prop rod, stick ,whatever to hold the hood up after you successfully detach the springs.