1973-87 Hood

[HotRodPC]

Yep, find you a replacement 73-80 hood. I'd install the braces for prevention purposes since this is common. As mentioned, it's caused by still hood hinges, so clean and lube the hood hinges real good, and keep them lubed. Like maybe everytime you change your engine oil, maybe a few drops of the used motor oil at the pivot points of the hood hinge.

Yours actually doesn't look bent real bad yet. That tip @Lastwords suggested may work to get it at least real close then add the hood braces or something equivelant that you might be able to make yourself.

 

[highdesertrange]

val is right. the hood is supposed to bend there in case of a front end collision. if it doesn't bend there you run the risk of the hood coming through the window and cutting you in half in a frontal collision. leave the braces off, and keep your hinge lubed. highdesertranger

 

[oreopenguin536]

good lord the smog guy of all people bent mine because he didn't know how to close the hood the right way…. last time I let ANYONE touch my truck for anything unless they have common sense….. I swear if some people had a brain they'd be dangerous

 

[firebane]

val is right. the hood is supposed to bend there in case of a front end collision. if it doesn't bend there you run the risk of the hood coming through the window and cutting you in half in a frontal collision. leave the braces off, and keep your hinge lubed. highdesertranger

The hood would crumple well before that even happened. Modern hoods don't even have that ability.

 

[HotRodPC]

The hood would crumple well before that even happened. Modern hoods don't even have that ability.

Believe it or not, it has happened. Not in many years, but cars are designed for the hood to crumple. It doesn't "just happen". Although, I braces are not that strong to keep one from folding. Now you use a 3in channel iron for a support brace with tough enough screws or bolts that won't sheer, then I'd say it's possible. If you use some self tapper screws I'd think they'd rip out of the sheet metal in a collision tough enough to put the hood through the windshield.

If you don't think it's possible, did you even wonder why vehicles have such hooks? The hook is designed to catch the cowel, stop the hood, then it buckles. Some are in the hinges, some are in the hood itself, and some are in the cowel that catch the hood. No matter the design, the purpose is the same.

 

[firebane]

Well yeah using a huge chunk of steel to prevent the hood from buckling would obviously do that but I would hope one who is putting some steel there to help the buckle would be smarter than that.

Regarding that hook... I have never seen that ever not on my truck or any of my previous trucks so I'm not sure what year that picture is from.

 

[HotRodPC]

That hook is on the 81 up squares built into the hood hinge. Some vehicles have it in the cowl to catch the hood. I know GMT 400 and 800's have it for sure too. Something as minor as those hooks have potentially saved many lives or at least limited injury in the right type collision conditions.

 

[Don5]

Believe it or not, it has happened. Not in many years, but cars are designed for the hood to crumple. It doesn't "just happen". Although, I braces are not that strong to keep one from folding. Now you use a 3in channel iron for a support brace with tough enough screws or bolts that won't sheer, then I'd say it's possible. If you use some self tapper screws I'd think they'd rip out of the sheet metal in a collision tough enough to put the hood through the windshield.

If you don't think it's possible, did you even wonder why vehicles have such hooks? The hook is designed to catch the cowel, stop the hood, then it buckles. Some are in the hinges, some are in the hood itself, and some are in the cowel that catch the hood. No matter the design, the purpose is the same.

Well I learned something new today. That was pretty interesting. I didn't know these trucks came with a hook built into the hood or cowl.

 

[bucket]

Well yeah using a huge chunk of steel to prevent the hood from buckling would obviously do that but I would hope one who is putting some steel there to help the buckle would be smarter than that.

Regarding that hook... I have never seen that ever not on my truck or any of my previous trucks so I'm not sure what year that picture is from.

Your earlier truck may not have them, but my later 70's trucks have the tall bolts at the rear. They are designed to fit into a slot in the hood when it closes, to keep the hood from going through the windshield in a collision. If the hinges are worn, the hood just lays on top of the bolts though. Also, there were some late 70's trucks (maybe all K5's?) that had a third 'tall' bolt mounted to the top center of the firewall.

 

[El Diablo]

Switching Hoods

Hey, just stumbled into this because I have a '73 K10, but a very straight '82 body on it. I want to return the front end to a '73 clip. From what I have learnt, this transfer is not too hard. The '80 plus have a air intakes on the Cab and the hood is therefore shorter. The '73 hood would extend across the full length of the hood, from the grill to the windscreen.

I only mention this because my understanding is that simply changing the whole front clip won't actually allow you fit an '80 hood to a '70 something truck, unless you're willing to fab something to fill the gap between the aft end of the hood and the windscreen.

That's my understanding? Any takers? Any alternatives that I'm missing?

In my case I'm going to replace the front clip and install a '70s fibreglass hood with a 4" cowl - 4 pins, lift on/off. I figure i can trim the hood to fit the front edge of the cab. Not expecting any issues with fenders, core support etc, though not sure if the doors are any different in terms of body line, '73 to '82?

Just my two cents .... Here to learn

 

[77 K20]

Your earlier truck may not have them, but my later 70's trucks have the tall bolts at the rear. They are designed to fit into a slot in the hood when it closes, to keep the hood from going through the windshield in a collision. If the hinges are worn, the hood just lays on top of the bolts though. Also, there were some late 70's trucks (maybe all K5's?) that had a third 'tall' bolt mounted to the top center of the firewall.

I know my dad's '79 GMC K15 has the 3rd tall bolt that fits into a hole in the center of the rear of the hood. Took me a while to find a pic online of said bolt:

You must be registered for see images

Also while searching I found an old crash test video of a '79 K20. You can watch the hood on that kink.

https://www.youtube.com/watch?v=DpvCDDtHnKc

 

[bucket]

Hey, just stumbled into this because I have a '73 K10, but a very straight '82 body on it. I want to return the front end to a '73 clip. From what I have learnt, this transfer is not too hard. The '80 plus have a air intakes on the Cab and the hood is therefore shorter. The '73 hood would extend across the full length of the hood, from the grill to the windscreen.

I only mention this because my understanding is that simply changing the whole front clip won't actually allow you fit an '80 hood to a '70 something truck, unless you're willing to fab something to fill the gap between the aft end of the hood and the windscreen.

That's my understanding? Any takers? Any alternatives that I'm missing?

In my case I'm going to replace the front clip and install a '70s fibreglass hood with a 4" cowl - 4 pins, lift on/off. I figure i can trim the hood to fit the front edge of the cab. Not expecting any issues with fenders, core support etc, though not sure if the doors are any different in terms of body line, '73 to '82?

Just my two cents .... Here to learn

You won't have to modify the hood, the cabs are the same shape. When you swap the '73-'80 front clip onto the truck with hinges and all, a '73-'80 hood will fit too. The wiper mounts will be too tall though, so those need changed to the '73-'80 style also.

 

[El Diablo]

Hood (aka Bonnet

[You won't have to modify the hood, the cabs are the same shape. When you swap the '73-'80 front clip onto the truck with hinges and all, a '73-'80 hood will fit too. The wiper mounts will be too tall though, so those need changed to the '73-'80 style also]

Ripper! Thanks mate!! )

 

[HotRodPC]

Yep, that's true, this is because the earlier hoods are longer that take up the space. The deal is, the earlier hoods and cowel are 1 piece, the later hoods are shorter because the hood and cowel cover over the wipers is 2 separate pieces.

There is currently another member doing this swap right now. He's got a mid 80's cab and he's putting a round single headlight front clip on the truck with earlier hood also which is 1pc hood and cowel.

Start with post #82 of Page 6 of this thread. He's putting a 73 front clip on an 83 cab.
http://www.gmsquarebody.com/forum/showthread.php?t=11942&page=6

 

[El Diablo]

Ripper

Perfect!!! Thanks Man!!!