I own a radiator shop and have to admit, I believe zirgo fans almost have to be way overrated! I have included an attachment that shows a finished project for a gut from wichita with a blown 502. He had a becool module that wouldn't cool his car. Becool blamed the motor which was removed and torn down 3 times and found nothing wrong!! I built a 4 row "bad ass" aluminum radiator and used a vintage air fan (Biggest fan on the market I can find but $$$) with a shroud/fan mount built by me. The results were that we had to cycle the fan or it would run only 150 degrees and that was in August. (slow drive or highway) I have to admit, however, that the radiator was huge (thickness) but was the same overall size as the becool and I baffled the inside to pass the coolant through three times in sections. I agree with one of the previous posts that a well thought system including the radiator, shroud and fan (whether elec or eng drivern) is key to getting results. I have been building custom aluminum radiators for awhile and many of them with electric fans and have only had problems with a couple of them and it was always due to some type of plumbing problem so far. All systems need a reservoir that has the capability of returning coolant to the radiator and not just a puke can. Puke cans are a joke and a waste of money. Most of the "pretty" polished aluminum tube reservoirs are very undersized and will not hold an adequate amount of coolant. I personally do not use anything smaller than about 3 qts and always have a tube or hose connecting the two of atleast 5/16 id. This is important! I am currently running a ATI blown 383 Z28 and built a huge innercooler and shitcanned the one that came with the system (tiny) and accompanied this setup with a twice as thick and shorter aluminum radiator (built by me) and am using the stock fans that came with the car and still have no heating problems with 650hp. Keep in mind that I believe these are two of the crappiest oe fans for gm v8's that I think I have ever allowed to be reused on anything and they still do the job but are a constant on setup. Just goes to show you that there are many variables when building a hotrod cooling system and you can tweak any of them and get results. Contact me if you have any hard to figure problems and I can probably help. I have been in this business for 25 years and have learned a few things and would be happy to help. Thanks, Topradman ps, I will add some pics but this file is already too big