The best 7 blade Ford fan is made by GM?

Hi guys,
My fascination this month is with fans. I truly believe that for our trucks with basically any engine, the best option is a clutch fan with possibly electric pushers up front for extremes and A/C etc. I know people who have had a clutch fail at an inopportune moment will disagree. To each his own.

That argument aside, what is the best clutch fan for a 460? I thought it was the 7 blade from the 70s trucks D8TZ-8600-A. That is 19.5" and has a 2.25" pitch, right? I've seen what looks to be a couple of different versions of these depending on what year truck they came out of. Not sure what the real difference is, if any. These are surprisingly hard to find. That's why I don't doubt that they are worth using.

However, I was really surprised when I read this post talking about the GM 7 blade 19.5" fan. The writer compares it to the Ford 5 blade fan over which it has a clearly significant CFM advantage. I checked the clutch specs (Hayden 2797 and 2799) and it seems that the clutches are identical with the exception of the pilot diameter, implying that the GM fan and Ford fan are completely interchangeable. Has anyone here ever compared these two fans side-by-side? Is anyone out there running the GM 7 blade fan on their Ford?

If not, is there anyone out there who has a 7 blade Ford fan sitting on a shelf? If so, I can get my hands on a GM fan and we can both post our measurements here and compare for everyone's benefit. Chime in here if you can help settle this.

Thanks!

I had a 7 blade fan years ago on a 1958 MEL 430 in a 1958 Country Squire it would move some air. What it came from, I am not sure, it came with the ex-NASCAR 430 I was given (belonged to Bill Champion and came with a Algon injection setup and headers that were obviously for a "Square-Bird" body).

The plot thickens!

I just found a Mopar fan from the mid 70's that might be the new reigning champion of CFM. Check out 3462186:



This is a 20" fan, so it might be too tight for a standard shroud (but I am currently running a 20" Derale in a standard 460 shroud without issue). The pitch on this fan is 2.75" versus the 2.25" on the Ford 7 blade. The clutch bolt diameter is still 3.25" so it should fit with a stock clutch.

I'm sure this thing sucks horsepower, but I challenge you to find a fan that will move more air than this on a BBF. And the best part is, you can actually find these fans just laying around!