67-8 vs 69-72 core support frame horn - The 1947 - Present Chevrolet & GMC Truck Message Board Network

BrianG · 03-13-2015, 08:12 PM

I am having some issues with the alignment of my front sheet metal. Particularly, it seems as though the core support is too high compared to the front of the cab. If the core support would go down a little then the alignment would be going much better.

So, while researching this, I have stumbled across a topic that seems to be truly unanswered or unproven. Some say that the frame horns that support the core support sit lower than the top of the frame on some years, and flush with the top of the frame on other years. I know that some (I believe 67-68) have a smaller hole in them also.

My frame horns are flush with the top of the frame. The mounts I have are approximately an inch thick, so the core support sits above the top of the frame by that inch. Is this normal? What would it hurt to take it down some? If I were to take it closer to the frame would that mean that my bumper will not line up with the grille correctly?

Can anyone provide proof that the height of the core support horn was ever not flush with the top of the frame. I don't need proof that it was flush, I have one that is.

Thanks for the help.

**68bowtie** · 03-13-2015, 10:17 PM

my 68 c20 horns sit flush with the frame. the washer/bushing between the support and horn is no where close to 1 inch...

**Boog** · 03-14-2015, 07:54 AM

The problem most likely is not with your core support mounts or cushions. Look at the cab mounts and cushions. They may be deteriorated enough to cause the cab to be too low to line up the fender.
If I'm not mistaken there are a couple different height cab mounts also. Maybe one for 2wd and one for 4wd trucks. Someone can confirm that?
Some pictures always help in these situations. We don't know if you are only replacing the front clip or doing a complete body off rebuild so particulars are important too.

BrianG · 03-14-2015, 04:19 PM

Quote:

Originally Posted by 68bowtie

my 68 c20 horns sit flush with the frame. the washer/bushing between the support and horn is no where close to 1 inch...

Interesting... Do you or anyone else have any pictures of the distance between the bottom of the core support and the frame? Pictures from all years welcome. This may help answer if there are truly differences between the years.

**FirstOwner69** · 03-14-2015, 04:37 PM

What year is your truck? 1/2 or 3/4 ton? Sounds like it's probably a 69-72, but I'm not sure.

BrianG · 03-14-2015, 04:55 PM

Quote:

Originally Posted by FirstOwner69

What year is your truck? 1/2 or 3/4 ton? Sounds like it's probably a 69-72, but I'm not sure.

Well, it will be a 69 4x4, but like I said, it is made up of various parts from various years.

1/2 ton 4x4 that is

**FirstOwner69** · 03-14-2015, 05:03 PM

Quote:

Originally Posted by BrianG

Well, it will be a 69 4x4, but like I said, it is made up of various parts from various years.

1/2 ton 4x4 that is

Is the frame from a 2WD 1/2 ton, 4WD 1/2 ton, or some other combination? Also, what year is the frame?

hugger6933 · 03-14-2015, 05:21 PM

If the core support is too high at the top the gap in the fenders is gonna be tight at the doors at the top and wide at the bottom. Of course it sounds like you have learned this on your own. From what I have determined the difference in the years model difference on the front body bushing is the size of the hole diameter and not the thickness. Where there are a difference in the thickness of the bushing is in the model of the truck. Now some may need to chime in here as I have not mapped this all the way out as yet but the C30 bushings are most def different than the ones for the C-10's. And the C and K series seem to be different so this is where some of the difference might come in.
Now what I would do is to hang the front bumper to see if the front is too high or the cab is too low.
Yes and I drum this into my dad's head every time he wants to try to "make "something fit you can't move one parts problem with out moving the problem farther down the line, and if you keep going by the time you get to the bumper you are liable to have a huge honking mess on your hands trying to line anything to anywhere near close.
So if the bumper doesn't look right when you sit it up on the brackets get some core support mounts that are one inch thinner than the ones you have now and you'll be good to go. If that makes any sense,and your frame isn't tweaked a little but I don't want to freak you out or panic you it sounds just like it is as simple as the wrong rubbers on the core support mounts.
Normally the frame horns are typically referred to as the forward part from the forward most cross member. Good luck and happy sanding. Jim

BrianG · 03-14-2015, 04:17 PM

It is at the end of a complete frame off rebuild. Or maybe I should say BUILD without the RE because it has many new parts or used parts from other vehicles. The cab mounts are new. I am having the same issue that I've seen posted here before, but I'm not really sure how each of those situations were resolved. The body line from the tailgate end of the bed all the way to the grille end of the door is straight. With the core support mounts that I have (69-72 style) the front appears to be too high. This caused the seam between the fender and door to not align well. Too close at the top and too far away at the bottom.

Again, is there any proof that the core support frame horns, mounts, perches, whatever they are called were ever not flush with the top of the frame. Looking through some pictures on this site, I have seen some core support pictures that appear to sit at least a half inch, to possibly almost an inch above the to of the frame. Is this normal.

What does not make sense to me is that if the 67-68 core support used a very thin spacer, then it would sit lower to the frame. The cab mounts are the same, so how is this resolved? Bottom line is, if I can lower my core support closer to the frame, it is going to help in the alignment of the fender to the door and help keep the body line straight. However, what other issues might I have if I do so? Will my bumper then not fit right to the grille? could I have other issues with the radiator or anything else?

hugger6933 · 03-14-2015, 05:22 PM

Sorry I usually reserve that tag line for the paint and body section. Jim

wannabefastcrf · 03-14-2015, 07:43 PM

I had a similar issue and I used a saw to trim 1/4 of an inch off the core support rubber mount.

03-13-2015, 08:12 PM	#1
BrianG Registered User Join Date: May 2011 Location: Oakley, Michigan Posts: 735	67-8 vs 69-72 core support frame horn I am having some issues with the alignment of my front sheet metal. Particularly, it seems as though the core support is too high compared to the front of the cab. If the core support would go down a little then the alignment would be going much better. So, while researching this, I have stumbled across a topic that seems to be truly unanswered or unproven. Some say that the frame horns that support the core support sit lower than the top of the frame on some years, and flush with the top of the frame on other years. I know that some (I believe 67-68) have a smaller hole in them also. My frame horns are flush with the top of the frame. The mounts I have are approximately an inch thick, so the core support sits above the top of the frame by that inch. Is this normal? What would it hurt to take it down some? If I were to take it closer to the frame would that mean that my bumper will not line up with the grille correctly? Can anyone provide proof that the height of the core support horn was ever not flush with the top of the frame. I don't need proof that it was flush, I have one that is. Thanks for the help.

03-13-2015, 10:17 PM	#2
68bowtie Senior Member Join Date: Jan 2007 Location: Turlock, CA Posts: 8,813	Re: 67-8 vs 69-72 core support frame horn my 68 c20 horns sit flush with the frame. the washer/bushing between the support and horn is no where close to 1 inch... __________________ Please help my sister in law with her battle with cancer https://gofund.me/902f6fce Thank you all so far you are angels!! Project "C10 Fever" (68 factory black 396 swb) Project "Little Sister" (70 c10 blue original paint refresh) Project "Blue Bomb" (70 c30 blue original paint refresh) SOLD Project "Vitamin C" (71 c10 orange original paint refresh) SOLD

03-14-2015, 07:54 AM	#3
Boog laying low Join Date: Mar 2001 Location: Searcy, Ark. USA Posts: 13,584	Re: 67-8 vs 69-72 core support frame horn The problem most likely is not with your core support mounts or cushions. Look at the cab mounts and cushions. They may be deteriorated enough to cause the cab to be too low to line up the fender. If I'm not mistaken there are a couple different height cab mounts also. Maybe one for 2wd and one for 4wd trucks. Someone can confirm that? Some pictures always help in these situations. We don't know if you are only replacing the front clip or doing a complete body off rebuild so particulars are important too. __________________ Boog 69 Chevy stepside, 358/T350, 4.11 posi, 4.5/4 drop, rallys, poboy driver primer is finer 91 Chevy sportside, Tahoe, Yukon & GMC Crewcab All GM..'nuff said. I stand for the flag and kneel at the cross

03-14-2015, 04:37 PM	#5
FirstOwner69 Senior Member Join Date: May 2010 Location: Wisconsin & Arizona Posts: 4,853	Re: 67-8 vs 69-72 core support frame horn What year is your truck? 1/2 or 3/4 ton? Sounds like it's probably a 69-72, but I'm not sure.

03-14-2015, 05:21 PM	#8
hugger6933 Registered User Join Date: Oct 2008 Location: Marianna Arkansas Posts: 7,280	Re: 67-8 vs 69-72 core support frame horn If the core support is too high at the top the gap in the fenders is gonna be tight at the doors at the top and wide at the bottom. Of course it sounds like you have learned this on your own. From what I have determined the difference in the years model difference on the front body bushing is the size of the hole diameter and not the thickness. Where there are a difference in the thickness of the bushing is in the model of the truck. Now some may need to chime in here as I have not mapped this all the way out as yet but the C30 bushings are most def different than the ones for the C-10's. And the C and K series seem to be different so this is where some of the difference might come in. Now what I would do is to hang the front bumper to see if the front is too high or the cab is too low. Yes and I drum this into my dad's head every time he wants to try to "make "something fit you can't move one parts problem with out moving the problem farther down the line, and if you keep going by the time you get to the bumper you are liable to have a huge honking mess on your hands trying to line anything to anywhere near close. So if the bumper doesn't look right when you sit it up on the brackets get some core support mounts that are one inch thinner than the ones you have now and you'll be good to go. If that makes any sense,and your frame isn't tweaked a little but I don't want to freak you out or panic you it sounds just like it is as simple as the wrong rubbers on the core support mounts. Normally the frame horns are typically referred to as the forward part from the forward most cross member. Good luck and happy sanding. Jim

03-14-2015, 04:17 PM	#9
BrianG Registered User Join Date: May 2011 Location: Oakley, Michigan Posts: 735	Re: 67-8 vs 69-72 core support frame horn It is at the end of a complete frame off rebuild. Or maybe I should say BUILD without the RE because it has many new parts or used parts from other vehicles. The cab mounts are new. I am having the same issue that I've seen posted here before, but I'm not really sure how each of those situations were resolved. The body line from the tailgate end of the bed all the way to the grille end of the door is straight. With the core support mounts that I have (69-72 style) the front appears to be too high. This caused the seam between the fender and door to not align well. Too close at the top and too far away at the bottom. Again, is there any proof that the core support frame horns, mounts, perches, whatever they are called were ever not flush with the top of the frame. Looking through some pictures on this site, I have seen some core support pictures that appear to sit at least a half inch, to possibly almost an inch above the to of the frame. Is this normal. What does not make sense to me is that if the 67-68 core support used a very thin spacer, then it would sit lower to the frame. The cab mounts are the same, so how is this resolved? Bottom line is, if I can lower my core support closer to the frame, it is going to help in the alignment of the fender to the door and help keep the body line straight. However, what other issues might I have if I do so? Will my bumper then not fit right to the grille? could I have other issues with the radiator or anything else?

03-14-2015, 05:22 PM	#10
hugger6933 Registered User Join Date: Oct 2008 Location: Marianna Arkansas Posts: 7,280	Re: 67-8 vs 69-72 core support frame horn Sorry I usually reserve that tag line for the paint and body section. Jim

03-14-2015, 07:43 PM	#11
wannabefastcrf Registered User Join Date: Dec 2013 Location: NW ohio Posts: 160	Re: 67-8 vs 69-72 core support frame horn I had a similar issue and I used a saw to trim 1/4 of an inch off the core support rubber mount.



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