Need a new radiator, '66

SadbutTrue

SadbutTrue

Founding Member
May 1, 2002
2,390
4
49
Granada Hills, California
#1
Well, I've needed one a while. Took my car out last weekend and it was running pretty well, but overheated. Actually, I'm positive the reason it overheated was the thermostat (it was literally a 2 mile drive and the motor wasn't even hot to the touch but i boiled off damn near all the coolant in the system), but my radiator is leaky and is an NPD repro that never has really done the job. I always heard even with a 289 the 65/66 radiators didn't quite come to task but with a modified 351 it doesn't even come close.

I remember hearing Northern Radiator was pretty good. I don't want to spend $500 but I'd be willing to spend to ahve something I'm confident will keep the car cool. Don't care about weight at all, fwiw. What design do I want? 2-3-4 core? Cross flow? Aluminum, brass, copper?

Also, I had heard and considered putting a 67-68 radiator in (probably an aftermarket one - basically whatever your ecommend for the 66 I'd get for a 67) to install. I realize I'd need to weld in new mounts... how hard is that/how much should a shop charge to do that? Would I need to make any other changes?
 

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#2
SadbutTrue said:
Well, I've needed one a while. Took my car out last weekend and it was running pretty well, but overheated. Actually, I'm positive the reason it overheated was the thermostat (it was literally a 2 mile drive and the motor wasn't even hot to the touch but i boiled off damn near all the coolant in the system), but my radiator is leaky and is an NPD repro that never has really done the job. I always heard even with a 289 the 65/66 radiators didn't quite come to task but with a modified 351 it doesn't even come close.

I remember hearing Northern Radiator was pretty good. I don't want to spend $500 but I'd be willing to spend to ahve something I'm confident will keep the car cool. Don't care about weight at all, fwiw. What design do I want? 2-3-4 core? Cross flow? Aluminum, brass, copper?

Also, I had heard and considered putting a 67-68 radiator in (probably an aftermarket one - basically whatever your ecommend for the 66 I'd get for a 67) to install. I realize I'd need to weld in new mounts... how hard is that/how much should a shop charge to do that? Would I need to make any other changes?
Click to expand...


Just get an aftermarket. Even with the 67-68's alot of times guys will get the "big block" radiators. I've got just a generic one from summit that works great. I drove it through 110* heat this summer with two core mounted fans (so its not even working that efficiently!) and it neve got above 185 standing in traffic. Also put one in a buddies 68 camaro that has a 350 with LOTS of power goodies in it. Handles it really well as well, with the motor at 2.5K in the shop with no external fan (just the radiator fan, shrouded) it would keep it at 170 constant.

Mine fit in well, but idk if you'd have some fitment issues in a 65-66, I'm not real sure on how much wider the core support is
 
#4
SadbutTrue said:
Well, I've needed one a while. Took my car out last weekend and it was running pretty well, but overheated. Actually, I'm positive the reason it overheated was the thermostat (it was literally a 2 mile drive and the motor wasn't even hot to the touch but i boiled off damn near all the coolant in the system), but my radiator is leaky and is an NPD repro that never has really done the job. I always heard even with a 289 the 65/66 radiators didn't quite come to task but with a modified 351 it doesn't even come close.

I remember hearing Northern Radiator was pretty good. I don't want to spend $500 but I'd be willing to spend to ahve something I'm confident will keep the car cool. Don't care about weight at all, fwiw. What design do I want? 2-3-4 core? Cross flow? Aluminum, brass, copper?

Also, I had heard and considered putting a 67-68 radiator in (probably an aftermarket one - basically whatever your ecommend for the 66 I'd get for a 67) to install. I realize I'd need to weld in new mounts... how hard is that/how much should a shop charge to do that? Would I need to make any other changes?
Click to expand...
The 64-68 radiator (except for the 67 BB and 68 AC and BB) bolted to the rad support. Problem with that is, the 67 opening is much larger than the 65. The BB/AC radiator used saddle brackets, top and bottom.


I have a 289HP, bored .030" over, with Ford AC in my 66. Like any late 66 factory AC car, I have a 3-row brass radiator, fan shroud, and thermal clutch fan. And no overheating problem. The beauty of this is, you could install the whole deal in an hour or two, with no cutting, drilling, or adapting.

This is not my car, but has the same setup-

TT1026.jpg
 
#5
Rusty67 said:
You didn't even ask me ?

Just go to radiator works. They will custom build one to your spec and it will keep the motor running cool.
Click to expand...

Well, I'll certainly hear what they have to say, but part of me implicitly trusts big business/Summit and dedicated national radiator shops more than local ones (which is unfortunate). And still am not sure on my 'preferred' order... X # of rows, brass/aluminum/copper, etc. Crossflow is better than 'downlfow', right? Summit aluminum radiators are all of $225-250.

When I say I don't want to deal with overheating again for 10 years, i am serious lol.
 
#6
Crossflow is better, but requires a matching water pump. Keep in mind that each additional row adds less cooling capacity. Diminishing returns - basically the air entering gets progressively hotter as it passes successive cores and has less and less cooling effect. A big 2-core is better than a small 4-core, even if the total cooling tubes should be the same length.

FWIW, I have a 2-core aluminum National rad with Hotrod electric fan/shroud cooling a built 331 (425-450hp). Since I got the thermal switch working properly, I haven't had an overheating issue. If you get an elec fan, pay attention to where you pull your 12V - make sure it is solid for both the motor and relay. Losing either is not good - ask me how I know. Because I have a MSD 7, elec fan, and one or two other switched 12V needs, I built a 12V buss near the battery with solid connections to power the relays. All good now. I made my own rad mounts from simple 90 degree angled sheet metal (stuff I had laying around - easily obtained) and common fasteners. Not hard, at all.

I have toyed with a big-block rad and enlarging the rad openning, but it hasn't proved necessary. BTW, I live in the inland SoCal area and see some hot temps.
 
#7
Was yours just a standard 65/66 plug-in unit? My stock/retro old 2 core radiator had at least a few inches to spare on each side that culda been used by a radiator... does yours still have that?

I added a newer style (exits the opposite side as my original 69 351w) Milodon high-flow water pump... would that be crossflow (it was for late 5.0s).

If yours is working for a 425 hp 331 it oughta work for me.
 
#13
On our classic Mustangs with Downflow radiator design, the inlet and outlet are both on the passenger side. The Waterpump hose connection is also on the passenger side.

When you swap over to a crossflow radiator, typically the inlet and outlet are on opposite sides. It’s easiest and cheapest to get one that has the inlet on the upper passenger side and therefore the outlet would be on the bottom driver side.

gri-1-26202-x.jpg

In order for the waterpump hose to connect to other side, it would take some creative routing. Instead it’s easier to get a waterpump with the connection on the driver side.
I added a newer style (exits the opposite side as my original 69 351w) Milodon high-flow water pump... would that be crossflow (it was for late 5.0s).
Click to expand...
What kind of water pump do I need to have to use a crossflow radiator? Will that 5.0 one I bought do it? http://www.summitracing.com/parts/MIL-16234 = what i got
Click to expand...
Other than the location of the hose connection, there is nothing that makes a waterpump a "crossflow pump"
You say you have a 5.0 type waterpump, then the lower connection should already be on the driverside. Is that how the lower hose is routed?
The Summit part you linked is Counterclockwise rotation. IIRC that means it is for serpentine belt drive applications.
 
#17
Tim65GT said:
On our classic Mustangs with Downflow radiator design, the inlet and outlet are both on the passenger side. The Waterpump hose connection is also on the passenger side.

When you swap over to a crossflow radiator, typically the inlet and outlet are on opposite sides. It’s easiest and cheapest to get one that has the inlet on the upper passenger side and therefore the outlet would be on the bottom driver side.


In order for the waterpump hose to connect to other side, it would take some creative routing. Instead it’s easier to get a waterpump with the connection on the driver side.


Other than the location of the hose connection, there is nothing that makes a waterpump a "crossflow pump"
You say you have a 5.0 type waterpump, then the lower connection should already be on the driverside. Is that how the lower hose is routed?
The Summit part you linked is Counterclockwise rotation. IIRC that means it is for serpentine belt drive applications.
Click to expand...

Thanks, helpful post :) Do you have a link to a radiator (or radiators) for my car?

A friend who builds restomods down south recommended this: http://www.mustangsplus.com/xcart/1965-66-Champion-4-Row-Aluminum-Radiator-Staggard-15690.html Its not crossflow, has 4 rows instead of the 2 for Summit. Obvoiusly the individual rows are smaller... I'm curious how they'd compare performance-wise.
 
#18
The Champion is not a "terrible" radiator, but that is a steep price for it. Check this:

http://www.ebay.com/itm/Ford-Mustan...es&hash=item1c28201a82&vxp=mtr#ht_8360wt_1094

Also, as SoCalCruizing said:

"Keep in mind that each additional row adds less cooling capacity. Diminishing returns - basically the air entering gets progressively hotter as it passes successive cores and has less and less cooling effect. A big 2-core is better than a small 4-core, even if the total cooling tubes should be the same length."

Oh, and here are all the Champions to fit your car:

http://stores.ebay.com/Atomic-Radia...g&submit=Search&LH_TitleDesc=1&_sid=996100510

HTH,
Gene
 
#20
horseballz said:
The Champion is not a "terrible" radiator, but that is a steep price for it. Check this:

http://www.ebay.com/itm/Ford-Mustan...es&hash=item1c28201a82&vxp=mtr#ht_8360wt_1094

Also, as SoCalCruizing said:

"Keep in mind that each additional row adds less cooling capacity. Diminishing returns - basically the air entering gets progressively hotter as it passes successive cores and has less and less cooling effect. A big 2-core is better than a small 4-core, even if the total cooling tubes should be the same length."

Oh, and here are all the Champions to fit your car:

http://stores.ebay.com/Atomic-Radiator/_i.html?_nkw=66 mustang&submit=Search&LH_TitleDesc=1&_sid=996100510

HTH,
Gene
Click to expand...

Any more definition on what constitutes 'big' and 'small' rows? Where's the tipping point?

chris66 - Definitely going to check to see if I can squeeze a 20" radiator in. There are definitely a few inches on each side of the stocker i'd like to use. Did you modify the mounts at all?
 
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