That would be a great idea. Even some of those old cast iron radiators would probably work much better than a barrel. Alas, I have only polyethylene barrels, so thats what I'll use for now. I'll keep my eye out for something like that though.
I decided to go with two barrels for a total of somewhere around 130 gallons. This should give me about 21,000 BTU of cooling. I'm curious how long the barrels will take to cool back down though. I guess we'll wait and see.
I got the parts together a bit so far. I grabbed my barrels to see what kind of fittings I could use with them. Looks like I should be able to use some 1/2" NPT fittings.
I also dug out my radiator. It measures 27" x 13" x 5/8" thick. I'm hoping since it helped cool a ~80hp engine it should be up to this task. I also grabbed some radiator hose for the main connections and plugged up the overflow nipple so it doesn't leak.
Tomorrow I'll try to go get the hose and fittings that I'll need. I'd ideally like to have this ready to go when the pump gets here so I can just plug it in and go. Its not supposed to be incredibly hot this weekend, but it won't be cool either. It would be a perfect time to test the setup.