Upgrade: Installing the longer 2WD 3/4 ton 454 radiator

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yevgenievich

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Agree on wire/components, but most of stock alternators in these trucks can't support the load. I tried to add 10 amp additional draw to charge some batteries while on a trip and the alternator just about took a dump. This is with suburban at night with front/rear ac on. Alternator should be upgraded first. Led light would be nice too. Also, to free up some power sanden ac compressor is a good upgrade over old r4. Twice the efficency. And brackets from vintage are $75. If you get the flx7, factory hoses will work.
 

austinado16

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Got it, thanks.
 

austinado16

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Replaced the fan clutch today with a Hayden severe duty version, and replaced the radiator hose with a version that comes straight forward, and clears the fan blades much better (Dayco 71422 - $11 at RockAuto).

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This is how the other hose fit.
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Camar068

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think i have it nailed down now with a 80 amp continuous duty relay

Any specs/numbers on the relay? Thanks M8. Don't wanna buy the cheap shart and regret it. Me and overheating have met too often in my lifetime to risk it.
 

NOPHO84K30

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Any specs/numbers on the relay? Thanks M8. Don't wanna buy the cheap shart and regret it. Me and overheating have met too often in my lifetime to risk it.

Its a spal fan controller that closes the relay at 185 . Now the constant 80 amp relay was just one they had there im sure its just a cheap one its all powered through a 100 a . Now that i have it it does take longer to get it under 175 it ran at 200 before i was told they iv454 ran hotter because it would burn more fuel efficiency idk if tgat was true or not. But it runs fine for now. we will see this summer at 115' in the shade. Lol
 

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Camar068

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Thanks
 

VaughnAK

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austinado16, thanks for the write up. This post has inspired me to upgrade the radiator in my truck.

I am converting a 1986 K20 to a big block. Once I got the engine and radiator installed, I found that the fan shroud for the 350 was too long to fit. My truck came from the factory with the 17" tall by 28" wide radiator; this radiator was never offered with a big block as far as I know. So if I want a functional fan shroud, I guess I'm buying a bigger radiator. Because of this post, I now know I can go all the way to the 19" tall by 34" wide radiator. I've been rounding up the parts to make this happen.

I'm sorry to see that your water pump shaft broke and took out your radiator. I like your idea of ditching the fan spacer and adding some metal flashing to the shroud to get the fan back inside the shroud. Did you ever add the flashing?

For what it's worth, GM made a reverse rotation, 20" wide, 9 blade, symmetrical fan under GM part number 15021599/ AC Delco Part number 15-80729. This fan fits inside the diesel fan shroud for the 34" wide radiator. It fits the Napa TEM 271302/Hayden 2784 big block severe duty fan clutch perfectly. These fans are getting hard to find new, but there might be another one or two out there.
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austinado16

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Sorry for the delayed response. Been wrapped up in life for a couple years I guess.

The license plate steps are probably no longer made, but they used to come up on ebay fairly regularly. I haven't needed or looked for one in years, so I don't know if they're still easy to find.

Regarding my fan shroud being too far away from my fan. YES, I finally did get around to installing a sheet metal band, to take up the gap. I met a guy who works for a local plumbing and heating place and he does all their custom duct work. I gave him the measurements and he made a nice one out of stainless. It bolts to the shroud. It's been on about 2 years now I think. I'm very happy with how the entire modification turned out, it works great, and I've put a lot of miles on it in the heat of the central CA valley, and towing in the heat and grades of the Sierras to the east of the valley (Kings Canyon and Sequoia Nat'l Parks).

I really like that 9 blade 454 fan a lot. Looks like it was used on Suburbans from '97-2000? It would be interesting to know which pulls more air, that bad-boy, or the 454 version with the giant paddles that I've installed. It was so hot coming back from Bakersfield last weekend on the freeway, that my fan clutch was engaging! It was kinda cool to listen to it start to come on, start making some extra noise, but not go to full lock and roar mode, and then cycle back off after a while. Outside temps were probably near 110*F. I was running both air conditioners...of course
 
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COK20

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Nice write up. That thing is wide.
 

Bextreme04

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Sorry for the delayed response. Been wrapped up in life for a couple years I guess.

The license plate steps are probably no longer made, but they used to come up on ebay fairly regularly. I haven't needed or looked for one in years, so I don't know if they're still easy to find.

Regarding my fan shroud being too far away from my fan. YES, I finally did get around to installing a sheet metal band, to take up the gap. I met a guy who works for a local plumbing and heating place and he does all their custom duct work. I gave him the measurements and he made a nice one out of stainless. It bolts to the shroud. It's been on about 2 years now I think. I'm very happy with how the entire modification turned out, it works great, and I've put a lot of miles on it in the heat of the central CA valley, and towing in the heat and grades of the Sierras to the east of the valley (Kings Canyon and Sequoia Nat'l Parks).

I really like that 9 blade 454 fan a lot. Looks like it was used on Suburbans from '97-2000? It would be interesting to know which pulls more air, that bad-boy, or the 454 version with the giant paddles that I've installed. It was so hot coming back from Bakersfield last weekend on the freeway, that my fan clutch was engaging! It was kinda cool to listen to it start to come on, start making some extra noise, but not go to full lock and roar mode, and then cycle back off after a while. Outside temps were probably near 110*F. I was running both air conditioners...of course
I have one of those fans and the clutch... it came on my 1997 K2500 suburban donor truck with the Vortec 454. I’m ditching the clutch and fan for dual electric fans.
 

austinado16

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Let me know if you'd like to sell the fan and clutch.
 

Vbb199

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Good writeup here @austinado16

Gives me idea for both my k5 with a 502 and my burb with a small block.

In the k5 I'm currently running just a 4 core 2500 radiator with a flex fan, engine stays around 208° just sitting and running for 30 minutes @ 9° BTDC.
I suspect when I turn it closer to 7, maybe 6, might start having cooling issues then.

Especially once I start pumping hot transmission fluid thru it from the sheer weight of the truck.

Although I am running efi, which leans and richens the AFR to keep Temps at the coolest it can.

I heard about windstar fans and lots of other options... Now I have more things to consider.


As for the burb, it's just a higher compression high output 350.
It was once a HD radiator truck with external oil cooler, now it's an aluminum radiator truck.
It never gets above 210 unless the thermostat decides to get stuck randomly, but generally on a hot summer day, running the AC, the truck may climb to 190.
I like to stay at 160, where it almost always runs at under normal outside conditions with no AC.

Having said all this, I got some things to think about to keep both trucks cool.
 

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