I would go with the original set up, but do like the idea of a larger radiator (as long as the fan isn't too close to it).

In the current non-original set up, the fan is too far away from the shroud.

Nice looking engine and engine compartment by the way.

 

Thanks Bill,

I like that idea too. I'll have to do some digging and see if an OE AC radiator will fit & bolt up to the non-AC spacer. It's actually cheaper than the non-AC radiator, and has a larger core (sounds like a win-win).

And thanks, I've probably done more painting under there than actual repairs!

 

I agree with @62BillT , your biggest problem is the fact that the fan is not within the shroud. whether the shroud is plastic or steel is irrelevant.
as for radiator being a Harrison, that's also irrelevant. the important thing is whether it is sized appropriately to cool an SBC.

 

Thanks Tom,

I guess I'm surprised that a shroud that's too far away is worse than no shroud at all (as in the factory setup), though I admit I'm no expert in fluid dynamics!

 

Agreed with them on the fan blades really needing to be partly inside the shroud edge.
I'd add that while the 4-blade steel fan is common OEM fan, it's not very good. You'd get better airflow using a factory one with more blades.

 

Sounds like there's a clear consensus regarding my fan placement!
That's a good point about having more fan blades. I'll have to think through the economics of that since OEM fans don't seem inexpensive

 

there was a comparison video I found awhile back

 

If you are also having issues when driving, you may have more than just a fan problem. Problems while driving usually mean it's coolant flow issue. I battled this problem for almost a full year. You may want to pull your intake manifold and check for leaks. Antifreeze becomes corrosive over time, and can cause all sorts of leaks. My original manifold had to just be tossed because the antifreeze had caused several fairly large holes.

I'm not really sure why the previous owners though the original fan without the spacer would be OK, puzzling decision. I decided to go aluminum radiator + electric fans on mine (with a shroud). With the original, your fan speed is very much limited by the engine vs electric fans.

 

With the original, your fan speed is very much limited by the engine vs electric fans.

Maybe so, but the original set up was designed by GM to work plenty sufficiently enough. Plus with that real nice all original engine compartment, I'm betting Mike would be wanting to keep that all original look.

That said, stepping up to an original type, era correct Clutch Fan may be an option to move up to, if a little more cooling is desired.

 

I tend to agree with 62BillT , a correctly configured setup as per GM is definitely adequate, as long as the radiator, water pump & cooling system in general is in good order, the situations that the standard system tends to faulter are usually going to be as modifications to the engine are made.

 

IMO I would not run without a shroud, the shroud (and it being effectively used, which it is not right now) allows the entire radiator to pull cool air through the heat exchanging area, not just the diameter of the fan leaving "hot spots" at each corner and reducing your cooling capacity by a significant percentage. If you can get a deeper shroud or a spacer for the current fan (don't love the idea of a spacer, if I were to do that I'd definitely give it some thread locker so the bolts don't back out due to vibration) I'd give that a try first.

Below is a pic from my '61, you can see the shroud is probably twice as deep as yours. I understand X frame cars probably have different radiator dimensions but maybe there's a deeper shroud available for yours. The fan sits basically centered on the edge of the shroud with maybe 1/2" clearance all around it so it is very efficient at pulling the air through. I don't have one from the rear of the radiator but can grab one this evening if you think it would be beneficial.

 

Well, '55 to '57 V-8's did not have a Shroud. The '58 to '64 V-8's did. Most '65-'66's didn't and '67 and up did have Shrouds. They were all designed by GM to work sufficiently. If someone has a modified car or modified engine, then opinions can differ, but if someone has an all original car and wants to keep it all original, there is absolutely nothing wrong with keeping it the way GM built it.

Although, I would add a 5 to 7 Blade Fan as has been mentioned above. Also, a factory Clutch Fan has at least 5 Blades and something that I would probably install along with a larger radiator, but just make sure everything clears just fine.

 

I don't mean to drag this on any more than it needs to.... but.... (lol)

Clearly you have several great paths forward to get to a desirable, functional, OEM-looking setup.
I can't stop re-visiting your description of the current overheating issue. I think there's an underlying problem still to be found & solved. I don't recall you mentioning if this is a recent overheating issue or if it's been there for the 2 years you've had it.

• At idle, the temp will reach 230 in just a few minutes
• When maintaining low speeds (<20mph), the temp will quickly climb beyond 230, causing some hesitation/bogging upon acceleration
• On the highway, the temp may reach 220+ when my foot is on the pedal for extended periods

Have you drained some coolant and removed the cap to visually check out the inside of the radiator to see if there's significant crud build-up blocking water flow?
Is there a chance that the carburetor is running really lean, making for an overly hot combustion?
Both upper/lower radiator hoses not going 'soft' and collapsing?
Where is the temp-sensor located, on the intake or in the head?
Sounds like the gauge is probably reading correctly, but it's always nice to be sure. Do you have a cheap infra-red temperature gun to spot check things?
While unlikely, I have to say "hopefully" someone didn't install one of those early 90's LT1 reverse-flow water pumps.

 

I agree. But since he has a serious Fan-to-Radiator issue, I would be starting there and then see how it goes. Good info though, if he has continued issues.

Mike, did you ever expect this much attention? Lol.

 

Just to add to BA.'s List, you should also test the thermostat, although I'd probably just replace it with a new one, they're not expensive & are recommended to be replaced when coolant is changed, so it might be overdue.