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wayneair 05-03-2007 10:58 PM

cooling question
85 monte carlo ss, dropped in a 350/ th400. electric water pump and 16" 2 speed fan w/ direct 16" shroud. question: is the OEM 305 radiator adequate for the 350? will be making 350 - 370 hp.

DeathRattle 05-03-2007 11:16 PM

I wouldn't think it would be up to the task at all.
Are you going to be running air conditioning?

wayneair 05-03-2007 11:23 PM

nope, no a/c ,no heater core.

DeathRattle 05-03-2007 11:31 PM

I guess you could try it and see if it stays cool. But adding all the horses you have has to be going way over what it was made to handle I would think.
What were the temps with the (maybe) 200 horse 305?
What is done to the 350 to get it into the 350+ horse range?

wayneair 05-03-2007 11:46 PM

i bought the car as a not-running project. as in, had a 454 bare block mocked-up in it. i have the 305 block, but i'll give it to you to use as a boat anchor. so i have no idea what normal operating temp was.

i have a rebuilt 350, .030 over, melling cam, 230/230, .480/.480, performer RPM man, 1" spacer, holley street avenger 670 cfm, iron heads med. porting, gasket matched intake and exhaust, flowtech afterburner headers, 1.6 roller and bearing rockers, electric water pump, elec. fuel pump, elec fan, HEI dizzy, msd 6al.

DeathRattle 05-04-2007 01:44 PM

With all the new horsepower it would be a gamble at best. I would spend a couple hundred on a good dual core aluminum radiator just to play it safe and to get it done right the first time.

BogiesAnnex1 05-04-2007 05:42 PM


Originally Posted by wayneair
85 monte carlo ss, dropped in a 350/ th400. electric water pump and 16" 2 speed fan w/ direct 16" shroud. question: is the OEM 305 radiator adequate for the 350? will be making 350 - 370 hp.

You'll hpefully forgive me for being a bit snippy, but!

I'm always spun around by guys who will spend heavy money on electric water pumps and fans and won't replace the radiator till disaster befalls them, or rather the engine that's attached to the old radiator.

A basic rule of thumb is, or should be, that every "new" motor gets all new coolant hoses and radiator. Do the heater core while your there. This should be first in your rebuild estimate for the simple reason is simply when these things let go, the likely hood of ruining your expensive hot rod motor is really, Really, REALLY high. The cost of this kind of a disaster doesn't offset the puny power gains that can be had with electric pumps and fans especially for a street driven engine.


docvette 05-04-2007 06:39 PM

doc here, :pimp:

A 305 radiator will cool a 350 Engine just fine....Provided both were stock, and used for normal street driven applications.

HOWEVER, This is not your will/Should Need to upgrade the cooling system to meet the needs of your Performance engine.

Besides that, you have no idea of the internal condition of the old radiator, or any idea of it's past abuses..It may just blow apart when you least expect it.

Cheaper to do it now, than it will be when the gauge hits 260 degrees..

Doc :pimp:

wayneair 05-06-2007 01:56 AM

what about a new one, the same size as the original? will it handle the extra hp? aluminum one row or copper 2 row?

wayneair 05-07-2007 05:37 PM


DeathRattle 05-07-2007 06:16 PM

Call up the major companies that make aluminum rads. Griffin, Be Cool, maybe some local shops?
I would expect to pay anywhere between 300-600 for a quality unit.
I have a becool single core. I paid 250ish. Says it will cool 350 horse easily. I have two 1200 CFM proform fans and a 35 GPM proform electric pump.
That cooling setup worked for my 357(died, for other reasons :( ). I don't know exact power output but it was an alright motor. 10.5:1, comp 270H magnum, stock heads, weiand manifold.
I now have 307 till I can get a 383 built. It should very easily handle the 307 but I doubt it will be adequate for the 383, unless I build a really crappy 383!

seriousracer 05-07-2007 07:29 PM

oldboogie is right.. alway maintain the radiator..
i have been running a 408 sm. in my 3/4 ton tow truck pulling trailer with out!! with out a clutch fan. and never use the electrics but in traffic.removing air form under the hood and good water to air (radiator) conductivity...

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