cooling my 406 - Team Camaro Tech
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post #1 of 9 (permalink) Old Mar 12th, 11, 10:28 AM Thread Starter
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Join Date: Jul 2006
Location: Lehigh Acres, FL
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cooling my 406

Hi guys,
New question--Still only have my 42 year old radiator. What path should I take to cool the 11:1 406 SBC?
Can I stick with the gm fan and fan clutch and go with a new aluminum radiator?
Is it worth having my existing radiator "reconditioned"?
Should i go for aftermarket aluminum radiator with electric fans?

I live in SW Florida, so summer is not pretty, but I drive it much more in the winter anyway, since no A/C.

Appreciate your input.

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post #2 of 9 (permalink) Old Mar 12th, 11, 11:23 AM
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Re: cooling my 406

If you have the original Harrison radiator it will cost big bucks to restore. Also they are hard to find now and you probably would get some nice coin for it if you want to sell it. I think aluminum is the way to go for your set up. Check out Great guy to deal with. He is a sponsor over at Team Chevelle.

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post #3 of 9 (permalink) Old Mar 12th, 11, 11:54 AM
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Re: cooling my 406

RJ WETHER it be a new brass or aluminum i would definatly put in a new 3or 4 core brass if its available or a new aluminum although i dont know how those are rated the tubes are bigger but i would always buy more than you need to cool that beast . I don,t believe that bs about 400,s running hot . I have seen a few through the years without problem. I have built about a half dozen for friends none of them were fancy .They were all cast piston stock rods and crank ,only 2 were sent to be balanced. I never used the stock heads mostly camel humps 1 with dart 180,s and i w vortec heads .all had aftermarket cams. For street beaters the ran pretty hard and durable 4 are still running .The other two sold the cars, all the engines had the sream holes drilled. HOPE THIS HELPS . ALEX
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post #4 of 9 (permalink) Old Mar 12th, 11, 02:02 PM
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Re: cooling my 406

Cooling a 406 is not tricky, treat it like any other smallblock making similar horsepower. I cooled my 11.5:1 406 with an electric fan and a replacement 3 core copper brass from performance radiator. I used a weiand wp. Washington is not, but on our rare 90+ days it never ran over 180.
I would run the best radiator you can afford, a high flow wp from Stewart, edelbrock etc. and the factory fan set up is a horsepower killer (somewhat), but probably better at cooling.


1968 rs with an old school 354" SB2.2 pump gas motor.

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post #5 of 9 (permalink) Old Mar 12th, 11, 05:03 PM
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Re: cooling my 406

Mine was fine with the 3 row 21" stock type replacement,mechanical fan,and shroud.

I went to an aluminum one of the same type/size and twin electric fans to save weight and stop robbing HP

68 Camaro~LSx ~all motor
1.54 60'--6.95 @ 98.45 660'--10.96 @ 121.53
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post #6 of 9 (permalink) Old Mar 13th, 11, 08:56 PM
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Re: cooling my 406

It was mentioned above, you will need the head steam holes to keep the coolant from boiling. As south as you are, no anti freeze is needed, use an alloy radiator, water wetter, electric fan mounted behind the rad and you will be fine.Even the best fan blade will cost you 20 H.P., I've always used a 160 degree stat with a few small holes drilled in it,no problem in the summer.
I drag raced a 415'' with pro action heads and no steam holes, and no problems, big power.I just picked up a new radiator from speedway for a 'chevelle, $140.
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post #7 of 9 (permalink) Old Mar 14th, 11, 02:27 AM
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Re: cooling my 406

I ran a flat top piston 64cc headed 406 with a 2 row 21inch radiator, factory and a Flex fan - it never over heated in MO. My latest is a 10.2:1 408 with a fan clutch, 7 blade fan, factory shroud, and a 23inch alumitech radiator and no steam holes - pretty confident it will not over heat. With an Edelbrock air gap manifold, there's 2 ports on the back of the manifold you can use to run coolant to the front by the thermostat that will help keep the cylinder temps balanced from front to back (back of the block runs hotter due to the way the water flows on a SBC). I chose to do that with mine using braided lines and an adapter from Jegs that goes between the mainfold and the outflow neck. The heads on this one are not drilled for steam holes, my machine shop that builds lots of 400s said it's not needed.

I would definitely run antifreeze to raise the boiling point of the coolant, prevents corrosion too.

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post #8 of 9 (permalink) Old Mar 14th, 11, 06:30 PM
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Re: cooling my 406

That's one thing I didn't think of, extra plumbing on the intake, good idea. Also use a ground strap on an alloy radiator to help prevent corrosion, and you can use a 20-25 lbs. rad. cap.
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post #9 of 9 (permalink) Old Jul 14th, 11, 08:09 PM
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Re: cooling my 406


Do you have a picture of how the coolant is routed with the Air Gap manifold? I would like to see how this is done. Maybe I will do it with the 406 I am putting together.

67 RS, 406 small block, TKO600, Moser 12-bolt (3.73)
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