73-80 vs 81-91 firewall

[K5_Sweden]

Shoot us picture of the dash, gauge area. Also maybe a pic of the fusebox. Sounds like you have a replaced vin tag truck.

The electrical looks like crap, but I guess that is to be expected on a 40 (!) owner truck…

Looking at it, I can’t believe it even runs! It didn’t pass inspection due to rusted out cab braces and no brake in the rear right side, but that’s it.

 

[K5_Sweden]

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.

Hmm, okey. Not quite sure where to look for that edge. But I will remove fenders for some rust repair, so it might be obvious when I see it.

Thanks, I’ll have a look at that too!

 

[500$k5]

73 to 80 dash cover, and gauge bezel, but 81 and newer fuse box. Wipers still in dash, dimmer switch still on the floor, so 81 to 83 cab?

 

[kennyw]

Hmm, okey. Not quite sure where to look for that edge. But I will remove fenders for some rust repair, so it might be obvious when I see it.

Thanks, I’ll have a look at that too!

Look at the two pics I posted side by side. I drew an orange line on the 81+ cab showing the transition you see on the 73-80 cab. You can see the edge once you pull the fenders for sure, but it may be possible to see without pulling them.

Another sign will be how clean the rectangular slot is cut. If someone modified a 73-80 cab, it will have rough edges rather than edges that are rolled into the cowl smoothly like the factory 81+ cab on the right.

 

[K5_Sweden]

73 to 80 dash cover, and gauge bezel, but 81 and newer fuse box. Wipers still in dash, dimmer switch still on the floor, so 81 to 83 cab?

Haha, this is ridiculous. It really is a mishmash bastard truck But thanks, every piece really counts in this rusty puzzle.

 

[K5_Sweden]

Look at the two pics I posted side by side. I drew an orange line on the 81+ cab showing the transition you see on the 73-80 cab. You can see the edge once you pull the fenders for sure, but it may be possible to see without pulling them.

Another sign will be how clean the rectangular slot is cut. If someone modified a 73-80 cab, it will have rough edges rather than edges that are rolled into the cowl smoothly like the factory 81+ cab on the right.
View attachment 473857

Thanks man, super clear instructions! I’ll have a look as soon as I can.

Unfortunately it starting to seem like the cab is 81-up, possibly 81-83 as 500$k5 said. If that’s the case, the tags have been swapped. Still have to find the stamped VIN, it seems plausible that this has not been changed.

 

[kennyw]

Thanks man, super clear instructions! I’ll have a look as soon as I can.

Unfortunately it starting to seem like the cab is 81-up, possibly 81-83 as 500$k5 said. If that’s the case, the tags have been swapped. Still have to find the stamped VIN, it seems plausible that this has not been changed.

Pull the dash pad, it is possible the original VIN is still under there.

 

[K5_Sweden]

Pull the dash pad, it is possible the original VIN is still under there.

Well, there we go. I found another VIN tag under the dash pad, and it says that my 1978 Blazer is in fact a 1982 GMC Jimmy

Thanks everyone for your time and effort!

 

[kennyw]

Well, there we go. I found another VIN tag under the dash pad, and it says that my 1978 Blazer is in fact a 1982 GMC Jimmy

Thanks everyone for your time and effort!

I would run the number through the Bumper app to be sure it is not stolen.

 

[K5_Sweden]

I would run the number through the Bumper app to be sure it is not stolen.

I ran it through two separate vin decoders online, and both said it’s not so I hope they’re right.

 

[K5_Sweden]

Another question popped up today when I unpacked my sheet metal order. The inner rockers are not for Blazer as advertised, but for C10. I don’t see how I’m gonna make it fit, but I haven’t taken off the rusted out parts yet.

Has anyone used these type of inner rockers on a K5? Is it a lot of work to make them fit or should I just send them back?



I tried to search the forum for the answer, but didn’t find any.

 

[Fastereddie]

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.

 

[jimmyleetn]

Another question popped up today when I unpacked my sheet metal order. The inner rockers are not for Blazer as advertised, but for C10. I don’t see how I’m gonna make it fit, but I haven’t taken off the rusted out parts yet.

Has anyone used these type of inner rockers on a K5? Is it a lot of work to make them fit or should I just send them back?

View attachment 473939

I tried to search the forum for the answer, but didn’t find any.

When I replaced mine I had to take a couple of the different inner rocker versions they made for the truck and pieced them together. They do not make one that actually fits a blazer/jimmy. Of course that's easier said than done for somebody in the states. If you had a metal break or access to one you'd almost be better off making your own.

 

[K5_Sweden]

When I replaced mine I had to take a couple of the different inner rocker versions they made for the truck and pieced them together. They do not make one that actually fits a blazer/jimmy. Of course that's easier said than done for somebody in the states. If you had a metal break or access to one you'd almost be better off making your own.

Thanks, then I’ll send them back and try to make my own. They’re $135 a piece after all.