The 1900cfm can be misleading... I don't think there's a 'standard' for listing cfm ratings. This fan has a super powerful 265W motor that is rated to pull a continuous 23.4 amps. (which is quite a bit of power) I tested it on my battery charger, and it showed a continuous 21 amps. It definitely blows a LOT harder than the old 16" fan that was on the car... even though it was rated close to the same cfm.

My old fan worked just fine until the temperature reached 90+, and I was just using Moroso belt drive for the water pump... (along with a griffin 2-core aluminum, stock sized but thicker radiator) The Derale should have no problem cooling pretty much any 65-66 mustang using an adequate radiator.

The Derale #16926 also has a built in shround that fits the radiator perfectly. Mount the unit with some weather stripping, and ALL the air the fan moves, will be coming through the entire radiator core.

There's a company (HotRod Air) that sells aftermarket air conditioning for early cars. They sell this fan (under their name) as a high power unit to be used with their AC systems for max efficiency.

I have seen this unit rated elsewhere at 2300-2400 cfm. It looks like an OEM unit, and has a top quality feel. I think it's under-rated in comparison with some of the other fans out there. It's definitely the best I've found that will fit a 65-66 mustang. (most are physically too large or thick to fit)



http://www.derale.com/electricfans.shtml

Good Luck!
[addsig]