There is a wealth of knowledge here, and I am trying to eliminate a possible overheating problem, so that's why I am asking this question, sorry if this is too basic a question. The car is a ’49 Cadillac, the engine is a 403 Olds, a new build, 20 over, mild cam, FlowKooler water pump and high volume thermostat (180 degree). Plenty of air flow through the front and the under hood area is open enough for plenty of air to escape. As far as radiator choices I have a ’49 Cad that has been gone through by a radiator shop and a new 3 core aluminum one, and I plan on running a 19’ puller fan (no clearance for anything else) with a 4 ‘ shroud. The electric fan set to come on at 170 degrees and there will be an AC condenser mounted in front of whichever radiator I use. So what’s your best guess on which radiator to use? Any input greatly appreciated.
I'd start with the radiator you have that has been "gone through". If it does the job end of story and you'll end up saving north of a grand for a high quality copper and brass unit. But if that's the way you want to go to start with be prepared to wait for a high quality unit such as one from Brassworks or Johnson's. JMO
The radiator with the most surface area. If they're the same, then try one, if it's not enough, try the other, if it's not enough figure out how to fit something larger in there.
I have a Copper/brass radiator in my '32 sedan, It's a Walker and has been in the car almost 40 years, If you intend on keeping the car and want a radiator you can depend on copper.brass is what all the major car manufactures used when these cars were new. HRP
My ‘49 Cad with a 429 Cad motor did not run cool enough with a stock radiator. The prior owner used a pusher electric fan because the 429 length did not allow fan space. I finally had to modify it by moving the radiator forward to allow space for a engine driven fan with a shroud and used a larger crossflow radiator. Runs cool now.
I'd start with the Caddy radiator. 170 seems pretty low for the fan turn on, I think 190 would be better. At 170 the fan would probably run almost all the time. You also need to wire in something to turn the fan on when the AC compressor comes on.
There is no sense in turning your electric fan on before the thermostat opens. Thermostat opens at 180, Fan on at 210 or 215 and off again at 190 or 195. The fan should not run when running down the highway, just in low air flow situations like stop-and-go traffic and parade duty.
I bought a cheap aluminum radiator for my 49 Buick, (same body as your Cad). It cools the 472 Cad motor just fine. Just measured the opening and bought one that would fit with a little modification of the mounts.
My 57 Tbird had some overheating issues when I first got it one of the biggest improvements was switching to an aluminum radiator I did buy a quality radiator that looks identical to the original Tbird rad. It was suggested to me by the shop technician at the CASCO restoration shop I had a hard time rapping my head around why aluminum would be better than copper/brass What I found after much research is 1) much of the copper/brass radiator is solder, which is a much poorer conductor than copper and brass and aluminum for that matter 2) aluminum in the construction of a radiator can use larger areas to flow better because it is stronger than the copper/brass metals I am running a 4 row Walker in my Roadster with a flathead with absolutely no cooling issues, my model A Tudor has an original round tube radiator and it works great Just saying don’t rule out an aluminum radiator if you are having cooling issues
I have aluminum radiators in 3 old cars, they all get too warm under certain conditions. And they were worse with copper/brass radiators, so that's not a solution either. They all could use something bigger...but there's not enough room, or no one makes one big enough. I guess I could move to Alaska
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