Your plan of going to the junk yard is a solid one. I went down the cheap fan route. Bought a electric fan from the local store, largest one they had (16 inch) was supposed to be good enough for a big block engine. I had two of them I mounted side by side on my diesel truck, would not cool it. Had them sitting around and decided to put one of them on my stock 2.9 v6. Would not cool even that little engine.
I went to the junk yard and got one of the famous 2 speed taurus fans. Mounted it in there and it cools it on high speed. I did not get fancy with some sort of low speed/high speed control. I just wired it for high speed. When it comes on sitting at a stoplight, I can watch my aftermarket temp gauge start falling.
One problem, when you get a real fan like this, they take real power to run them. I checked the cheap aftermarket fan, it took about 8 amps to run it. The taurus fan took about the same amps on low speed, but took about 12 amps on high speed. So I had to make sure I ran a relay, I was using the direct style temp switch and I was afraid it would not handle that long term. It did load the stock alternator down pretty good, but it handled it ok.
P.S. You can get the taurus fans new on Amazon if I remember correctly. Do not know about their quality though, I found a used one cheaper at the junkyard.