# Cooling for stroker question



## bondobill (Oct 24, 2011)

With Brent deciding on going with a stroker and edelbrock heads on his 68 400 will the stock radiator be suffice ? It's a non A/C car
If not what have some of you gone with as far as a radiator ?
Would electric fans be required ?
With the engine out I am thinking now would be the time to upgrade cooling if needed.

Thanks
Bill


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## Bensjammin66 (May 12, 2009)

My '66 was an iron headed 455 with a XE274 cam and it made decent power so it also made more heat than stock. My stock radiator was not enough. 195/205 at freeway exits and stop lights was common in summer and a bit scary till i got moving, then it dropped to 190ish.. 

Is he running an auto or stick? If auto and he doesnt mind an external cooler just grab a 2 row all aluminum one from Summit with 1" tubing. That same motor would consistantly run 180 with a 160 stat in it cruising. Even beating on it and coming to a stop light I never saw above 195 again. 

I think I paid $179 for the radiator and I paid $125 for a dual fan setup with shroud from a mercedes benz off craigslist that fit with minor trimming. Careful with huge fans and a weak alternator though, they keep things frosty but it pulls an incredible 60 amps! Didnt know that till afterward.... IMO working with a factory type electric fan is more reliable and affordable than aftermarket units. They get the job done protecting your investment. 

Just my .02


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## TK69tempest (Feb 28, 2011)

My '69 has a '67 400 with 4X-7 heads and XE274H cam. I put in a 2 row aluminum radiator with two 14" electric fans = it ran hot when standing still (215+) and warm when moving(195). I pulled the 2 row out and put in a 4 row, used the same two fans, but added a shroud = all is well now. It runs as cool as you would like it to be.

My two cents - especially after my trial and error - buy the biggest/best radiator and fan setup that will fit your car and your budget. Doing it while the engine is out is a lot easier than going back and redoing it with everything in the engine compartment.


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## BearGFR (Aug 25, 2008)

Just remember the key to keeping a Pontiac cool is in the water pump divider plate clearance. Sitting idling in a closed garage, my 461 tended to get too warm even with twin electric fans and a custom Mark7 aluminum radiator. Once I remembered I hadn't clearanced the plate and corrected that, I was amazed at how much difference it made. Now, even in the heat of a Texas summer with the A/C running, it rarely gets above the thermostat set point.

Bear


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## TK69tempest (Feb 28, 2011)

I totally agree with Bear. I double checked, then had a friend check the backing plate clearance to make sure it was OK.

There are so many conditions that can create extra heat in the engine - timing, carb mixture, etc. - I checked and rechecked everything I could think of - finally I decided that I was being foolish trying to save $ on the cooling system after spending so much time, effort, and money on the engine and drivetrain. I bought the 4 row aluminum radiator (which was thicker and held more fluid than the two row) and added a shroud system to the twin fans. Everything appears fine now - I've installed different thermostats, and whatever temp I put it, that's where it stays.

One more thing to remember that never hurts - drill a small hole in the flange of the thermostat to allow the engine to "burp" and purge the air out of the system.

Bear - love the avatar - the shirt is dead on awesome... TK:cheers


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## bondobill (Oct 24, 2011)

Thanks for the response guys.
Hey Bear, I saw a topic on here somewhere, you explained the process of tweaking the divider plate clearance. Will give that a try.

I would guess he is going to have a issue with the cooling of the rebuilt engine, it ran a little hot a couple of times before we pulled the engine.



Bill


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## Instg8ter (Sep 28, 2010)

Like Bear said, the clearance on the pump plate is single best improvement and its free. Next would be a shroud correctly mounted halfway over the clutch fan blade. Third would be radiator upgrade. If i had any hair i could blow dry it with the air mine pulls through the shroud sitting still, never once have i seen it above my therm temp, if anything i may put a 190 degree back in it to make it run a bit hotter and more efficient.

I set the plate on a sandbag and tapped down the edges until the clearance to the impeller blade was within 1/8" all the way around it when test fitted with the gasket in place. The impellers on aftermarket pumps are sometimes pressed deeper on the shaft than the stock ones creating over 1/4" gap ruining the water moving ability of the impellers to force water through your engine. Cooling is all about exchange rate of the water and surface area of your radiator fins. The Shroud is also a must for the same reason, it makes the fan suck air across your radiator even when at a stop.


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## geeteeohguy (Feb 2, 2008)

Everything else being equal, when you add cubic inches, you need to add cooling capacity. A radiator that was marginal with a 400 will not do well with a 461. Do the improvements stated, but be prepared to upgrade to a larger capacity radiator.


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## bondobill (Oct 24, 2011)

Anyone running a Champion aluminum radiator ?
I know they are made in China but ......so is most of the GM pickup I drive

Bill


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## Instg8ter (Sep 28, 2010)

yes i am and have been happy with it good value for the price.


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## bondobill (Oct 24, 2011)

Instg8ter said:


> yes i am and have been happy with it good value for the price.


Thanks
So how many row did you go with ?

I see we can get a 3 row for around $210

Bill


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## Instg8ter (Sep 28, 2010)

i got the 3-row, think i picked it up for 160.00 3 years back


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## TK69tempest (Feb 28, 2011)

The first one I put in was a Champion two row - like I said, it was close to OK when the car was moving, but got hot when it was still. The second was a four row - also Champion. The core and the tanks are a little thicker, so I had to change all of the mounts that I made to accommodate the bigger size. All-in-all I am happy with their units.


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