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73-80 vs 81-91 firewall

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K5_Sweden

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Hi guys

This is my first thread so please bear with me.

I have a ‘78 K5, with a 81-up front end on it. I really prefer to older style front with the round headlights and front fender body line, so I’m gonna try to gather the parts needed to go back to the stock look. Not an easy task in Northern Europe…

The motor is from 1978 and the TH350 is what it was supposed to come with, the dash also seems to be the 73-78 style. I can also see that the body used to have a different paint job than the front, the door jams are blue and the front fender are brownish metallic paint. The truck now has a hideous matte black paint job that’s peeling all over, have not been able to found out the original color.

As far as I understand, the 73-80 hood hinges differs from the 81-up. I can’t see any mounting holes or pockets to fit the older style hinges in my fire wall.

So my question is, do the fire walls differ in any way between the older and newer?

If yes, it seems that some previous owner really went out of his way by replacing the fire wall when updating (or downgrading in my opinion) the front end. IMG_4335.jpeg
 
Ah, ok. That makes sense, thanks!

But wouldn’t that mean that I have the newer fire wall since it could accommodate the new style hinges? Or at least that whoever changed the front cut it up to make room.
 
K5_Sweden said:
Ah, ok. That makes sense, thanks!

But wouldn’t that mean that I have the newer fire wall since it could accommodate the new style hinges? Or at least that whoever changed the front cut it up to make room.
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firewall is the same; once you get the newer style sheet metal off the older style should just bolt up. you will need a complete front clip with core support. the older style does not have the cowl piece; the hood goes to the windshield.
 
Great, thanks.

I ordered some sheet metal today, rockers, kick panels etc. Floor panels will be back in stock this fall, unless I want to shell out $505 for shipping alone and order from LMC or Summit racing
 
Ouch on the shipping. On the firewall, either someone did a lot of work or it is a newer truck with an older tag on it. I’ve seen that a few times.
 
That was my first thought too, but I’m pretty sure the dash, motor and tranny are from ‘78. I haven’t found any other easy way to determine the year other than VIN. Also the orange plaid seats with brown vinyl sides were supposedly an option only available in ‘78 and ‘79. At least that’s what I got from some old Blazer brochure I found online.

15 years ago I had a C10 stepside with the wrong tags on it, it was an older title on a newer truck. So you could be right.
 
K5_Sweden said:
That was my first thought too, but I’m pretty sure the dash, motor and tranny are from ‘78. I haven’t found any other easy way to determine the year other than VIN. Also the orange plaid seats with brown vinyl sides were supposedly an option only available in ‘78 and ‘79. At least that’s what I got from some old Blazer brochure I found online.

15 years ago I had a C10 stepside with the wrong tags on it, it was an older title on a newer truck. So you could be right.
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I noticed the big bump out on the left side of your firewall. My 80’s trucks do not have that so it probably is an early firewall just converted. Hard sayin’ not knowin’ haha.
 
Haha, I’m just guessing and assuming here so I know the feeling

Anyway, thanks a lot for the answers guys!
 
Welcome @K5_Sweden

We have another member in Sweden, been a bit since we heard from them. Middle pandemic. I'll have to look into who.
 
Thank you very much!

Interesting, I don’t think Blazers are very common here. There’s an old Suburban driving around where I live, but that’s the closest I’ve seen in a very long time.
 
Vin # on frame is typically not altered..that would tell part of the age

,??? Older models had tags with special shaped rivets on door post.

Tags on glove boxes have numbers+ build sheet options.

Newer vehicles had tags on dash.
 
So it turns out I have the three bolt mounting hole pattern for my wiper gear, which means 81-up according to @kennyw ’s nice piece of info. The VIN plate on door post is mounted with regular pop rivets, so in conclusion I have no idea what’s going on here

Haven’t been able to locate the VIN on the frame rails though, if I find it maybe I’ll learn more. No tag in glove box either.
 
Shoot us picture of the dash, gauge area. Also maybe a pic of the fusebox. Sounds like you have a replaced vin tag truck.
 
K5_Sweden said:
So it turns out I have the three bolt mounting hole pattern for my wiper gear, which means 81-up according to @kennyw ’s nice piece of info. The VIN plate on door post is mounted with regular pop rivets, so in conclusion I have no idea what’s going on here

Haven’t been able to locate the VIN on the frame rails though, if I find it maybe I’ll learn more. No tag in glove box either.
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The next clue is to look at the edge where the fender mounts. Notice they are very different shapes. The edge has a transition on the 70s cabs vs being straighter in the 80s cab.

Swapping the 80s front fenders on the 70s cab requires using the newer 3 bolt wiper transmission as they are longer to go through the cowl. However, the bolt hole patterns are not quite the same and it is typically a little butchered in the process since people know they can hide it.

You would need a mirror to find the frame serial number as it is stamped on top of the passenger frame section.
 
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