Need help with radiator questions

[Lobo'74]

The radiator in my '67 is new, but it is the small one for an inline six. I ordered a shroud and the hardware for a heavy duty 4 core radiator. I then ordered a heavy duty radiator locally. The firm said they used a three core as the 4 core had smaller passages and clogged up more - but they said their 3 core was the same thickness as the 4 core.

Well.... the 3 core is the same thickness as the one I have now, just longer. So I have a set of 4 core hardware thats too big for the new radiator, a 4 core fan shroud, and a 3 core radiator.

The truck runs hot now. Anyone gone from a three core to a four core? Does it make a difference? Are 4 cores more susecptible to clogging up, or was that a sales technique?

I'm trying to decide if I send the radiator back and get a four core, or keep the three core and send back the mounting hardware and cushions and shroud and get three core mounting stuff.


Thanks for any help.

[stelth2002]

I have a BIG 3 core in mine thats new. I orginally had a small 2 i think. A fan shoud is a must for city driving, however im mostly on the high way and i took it off and put on a clutch fan. Its worked perfect even during the 110 degree weather. I would warrenty the radiator and get a "4 core" or if they wont then just get the 3 mounting hardware. I dont think with that engine a radiator would be the problem. Thermostat, hoses, etc?

[jef5150]

im probably wrong but, i believe 4 cores, have a little smaller inside diameter tube,than the 3 core,it has something to with radiator width,,,,

[JimKshortstep4x4]

I have had good luck with the four cores and given a preference I would go with the four core. I have also had good luck with the three cores but I have used them to replace two cores.

The radiator shop where I have gotten work done for the last twenty years tells me that they can get "almost" the same capacity in a three core as a four core because the four core restricts air flow. They have not seen the plugging up as you were told, (unless they meant the air flow side).

If you have a three core in there now and are having problems
then I would definately go with the four core.

Jim

[Lobo'74]

The engine is pretty hot. 1979 350 Chevy V8, 4-bolt mains, with the following mods:

*Bored .030 over
*Align bored
*Parallel top of block
*New cam bearings
*New freeze plugs
*New hypereutectic pistons, flat top
*Reconditioned connecting rods
*Crankshaft main and rod journals ground .010 under
*Rotating assembly balanced
*Double roller timing chain
*Melling high volume, high pressure oil pump
*Speed Pro cam: Intake 224 deg dur, .450” lift; Exhaust 224 deg dur, .460” lift
*New hydraulic lifters and push rods
*World Industries part #012250-1 Sportsman II cylinder heads with 72cc chambers (9.5 to 1 compression), stainless steel valves 2.02 intake, 1.6 exhaust, heavy-duty valve springs, screw-in studs, guide plates
*Crane roller rocker arms (Rollers on both fulcrum and tip)
*Edelbrock # 1470 750 CFM 4-barrel carburetor
*Edelbrock performer RPM aluminum intake manifold
*HEI distributor (Late-70’s style)
*Dyna-max Headers

Thermostat is 190 degrees. Hoses are OK. The last owner has a kludged up plumbing type pipe set up to get the lower hose around the fan blades. A shroud and the correct hose should solve that, but the hose itself is fine. Good flow.

As long as the truck is moving it runs 190 degrees. Slow traffic 210. Stop and go, 230. I think the lack of a shroud causes it to run hot in traffic and when stopped. I think the V8 size radiator will be needed (about 29 inches wide) as the 6 cyl radiator (at 26 1/2 inches across) is smaller. I'm not sure if the 3 core will be sufficient or if the 4 core wound be better for cooling - then the question is , does the 4 core really clog up more or was that told to me because their shop doesn't carry the 4 core radiators?

[Lobo'74]

Yes, I tkink it was the clogged air flow that the supplier was talking about. Narrower passages that are thicker and tend to have airflow problems.....