Radiator mounting differences?

[AuroraGirl]

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This is my current radiator, and it's smaller. Im guessing it's standard cooling? I am going to switch to a factory heavier duty radiator. My dad has the same one. Here is his:

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I have the top bracket that makes it flush with core support. Is that the only difference or would the bottom have a different mounting solution? And where does one find the shroud?

 

[AuroraGirl]

From my 1980 service manual, I found that the top retains the radiator to the truck but the bottom has a sandwich buffer thing, It appears the same no matter AC or not, big rad or not.

THe top cover I show is not anymore necessary than mine in the switch, because its only to support the rad from further away and cover a condensor, it seems.

 

[C10MixMaster]

From my 1980 service manual, I found that the top retains the radiator to the truck but the bottom has a sandwich buffer thing, It appears the same no matter AC or not, big rad or not.

THe top cover I show is not anymore necessary than mine in the switch, because its only to support the rad from further away and cover a condensor, it seems.

Your top picture is what came in my 77 it was rated as a heavy duty cooling with a/c and it came with a 350. The bottom picture is what i would consider a big block radiator it is 2 inches taller. Yes cooling systems bigger is always better ,however I can't imagine you have a heating problem that far north? Looking at the spec catalog for my 77 there were at least 70 different combinations of radiators and fans for just that year. The bottom mount is the same for all of them . The mounting pads came in at least 2 and possibly 3 different sizes depending on how thick the rad is.

 

[AuroraGirl]

Its not that I have current cooling issues in winter time, which is where my use is, but it DID see some high temps with my on-property use here in summer time, but not extensive or past 215 as my thermal temp thing read, but I broke the nipple on current rad and this one was laying in my shed. So if I have it cleaned and it dont leak, I would like to switch to it..

Do you think i would have fitment issues since I have the top cover support?

The radiator on the second pic matches the one out of a 78 K10 with a 400 and trailer package, heavy duty cooling, trans cooler, and an auxillary oil cooler in front of rad.

 

[C10MixMaster]

Its not that I have current cooling issues in winter time, which is where my use is, but it DID see some high temps with my on-property use here in summer time, but not extensive or past 215 as my thermal temp thing read, but I broke the nipple on current rad and this one was laying in my shed. So if I have it cleaned and it dont leak, I would like to switch to it..

Do you think i would have fitment issues since I have the top cover support?

The radiator on the second pic matches the one out of a 78 K10 with a 400 and trailer package, heavy duty cooling, trans cooler, and an auxillary oil cooler in front of rad.

you have the big block radiator and top radiator support for it ,your most of the way there. When i did mine i had to add blind nuts to the core support where the upper radiator support bolts down ,the holes were already there but no nuts. and the pads will probably need to be matched to the rad.

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[AuroraGirl]

those look like nutserts, i went happy with them in my engine bay the day i broke the nipple.. lol i like them. But good to know about the holes. I prob have some nutserts that will fit that bolt. can i reuse bolts from the top support is?

and yeah, his is a 400 sbc with heavy duty cooling from montana and had AC.
i can buy pads. lower mounts should be same tho?

 

[C10MixMaster]

those look like nutserts, i went happy with them in my engine bay the day i broke the nipple.. lol i like them. But good to know about the holes. I prob have some nutserts that will fit that bolt. can i reuse bolts from the top support is?

and yeah, his is a 400 sbc with heavy duty cooling from montana and had AC.
i can buy pads. lower mounts should be same tho?

The lower or main radiator support is the same for all 75-80 c/k trucks

 

[AuroraGirl]

Just the insert pads change?

 

[C10MixMaster]

Just the insert pads change?

yes

 

[AuroraGirl]

Awesome.

What changed in 81? Core support? All of it?
I know an 80 with first year square eye could have a different core support(new product on LMC) because of that

 

[C10MixMaster]

Awesome.

What changed in 81? Core support? All of it?
I know an 80 with first year square eye could have a different core support(new product on LMC) because of that

80 is actually a round eye rounded front fender but there was a square headlight option. 81 was front end redesign headlights hood fenders etc.and core support.

 

[AuroraGirl]

80 is actually a round eye rounded front fender but there was a square headlight option. 81 was front end redesign headlights hood fenders etc.and core support.

thats what im saying. i have a 80 round eye, but lmc lists a grille JUST for 1980 GMC, which i assume is the optional square?

the only stock way to do 80 square eye front end on 73-80, i assume

 

[C10MixMaster]

thats what im saying. i have a 80 round eye, but lmc lists a grille JUST for 1980 GMC, which i assume is the optional square?

the only stock way to do 80 square eye front end on 73-80, i assume

1980 used a unique grill but it was used on the round and square light version, the lights and the headlight bezels were the differance.

edit : looks like lmc now has a 1980 core support that appears to have a few different holes in it. there old catalog, the one i was referencing, showed 75-80 as the same. It's probably one of those situations it would work but there's some differences.

 

[AuroraGirl]

I should look at what mine has, maybe its an option list thing like ac, ps, cooler, headlight, etc

 

[Bextreme04]

I should look at what mine has, maybe its an option list thing like ac, ps, cooler, headlight, etc

Mine is a 1980 K25 Sierra Classic with 350/TH400/205 and is an 8600 GVW with the heavy duty front spring option. It came factory with the square headlights, the same 4-row large radiator as your dads rig, and AC. The square lights in 1980 were part of either the Sierra Classic, Silverado, or Sport trim packages. You couldn't have a square headlight in 80 without one of those packages as far as I know. Mine does not have heavy duty cooling option, so maybe the larger radiator is due to either the factory AC option or the 8600GVW. My fan shroud looks different than your dads. Mine is 2-piece and fully encloses the fan. I'll be pulling it when I do the engine swap and going with dual electric fans, but keeping the 4-core radiator.