Need a new radiator, '66

iskwezm said:

The Summit's are made by Northern. I have a universal Summit(Northern) and it works great cooling my combo.

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same here. I was driving in 100*F heat last year with just two core-mounted radiators (hadn't gotten around to a proper shroud yet) never got above 190* in town. Also I was able to get mine with the inlet/outlet on the "stock" sides

more specifically:

http://www.summitracing.com/parts/SUM-CSUM3800/

Shows two 1" cores. For an automotive application thats about perfect.

SadbutTrue said:

a GM forum asked me to check if a Mark VIII fan would work. A lot of people there were recommending running both an electric and a flex fan until I showed them how much space there is in a 66 mustang engine bay :o

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only somone from a GM forum would suggest something as stupid as running an electric and a flex. ....why....just why..

this how much i opened mine and also gave more clearance to the water pump.

Here is a link to my install:
http://www.stangnet.com/mustang-forums/threads/northern-radiator-taurus-fan-install.698848/

This is one area I have some expertise. My younger brother is the design engineer for Northern. First off I will tell you that my 347 @ 460+ HP was the design mule for the Northern alum rad. It's a two row down flow stock replacement unit. It will cool just fine as long as you have good air flow through the rad. Air flow is more important that the size of the radiator. The later model cross flows are better but the plug and play of the original is a big plus.
The large tubes of a two row alum actual have more surface area exposed to cooling than a 4 row brass. They are much stronger so you can add a higher pressure cap they have no dead areas where the tubes are soldered to the tank bottoms. Just get the summit brand (Northern) but be sure and have a good electric fan or get the universal shroud kit and a good fan. Not one of thoughts small blade flex fans either. It has to be a fan that will pull air through the rad at slow speed. If you do this, it will cool a 500 plus HP motor all day long. If it were me I would get a 17" electric fan and shroud. That will end your problems.

By "big" I meant area of the radiator (width x height), not tube diameter. That said, I believe mine uses a 1" tube. A decent 2-row 20" rad in alum will cool a lot of engine. Maybe 500hp worth of motor.

65FBE2 said:

This is one area I have some expertise. My younger brother is the design engineer for Northern. First off I will tell you that my 347 @ 460+ HP was the design mule for the Northern alum rad. It's a two row down flow stock replacement unit. It will cool just fine as long as you have good air flow through the rad. Air flow is more important that the size of the radiator. The later model cross flows are better but the plug and play of the original is a big plus.
The large tubes of a two row alum actual have more surface area exposed to cooling than a 4 row brass. They are much stronger so you can add a higher pressure cap they have no dead areas where the tubes are soldered to the tank bottoms. Just get the summit brand (Northern) but be sure and have a good electric fan or get the universal shroud kit and a good fan. Not one of thoughts small blade flex fans either. It has to be a fan that will pull air through the rad at slow speed. If you do this, it will cool a 500 plus HP motor all day long. If it were me I would get a 17" electric fan and shroud. That will end your problems.

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pulling air through slowly actually isn't the best approach. You get a change in air velocity due to the pressure drop across the core. Having a shrouded fan with a high(ish) cfm is the most important. The bigger problem with the 4 row brass radiators is that with that many cores, your potential delta T is quite a bit lower once you get further through the rad. Then it basically turns into a big heat sink. Also there's no doubt that the "larger tubes" of the two row aluminum's will help with cooling (a little bit) but the increased airside hydraulic diameter due to those tubes has minimal effect. Its all about pressure drop, core type and proper fluid flows. You can always push more water through the system if a larger fan/radiator isn't available. Lastly a cross flow vs downflow radiator has almost no effect. In fact the downflows are more desirable because you get a natural heat pump effect due to the cooling fluid.

I realize that this was purely a design conversation and that in the end, just buy a northern that will fit in your engine bay, and put a proper fan on it and you'll do just fine.