94 Fan Blower upgrade w/part #

[SilverMiner]

Okay, after reading the recent thread about "better AC in 20 minutes" I finally ordered a new fan blower from a '94 Chevy Pickup for my 1980 Silverado Suburban with A/C. I purchased the new fan from NAPA and the part number I bought was 655-1744. Please let me know if anyone disagrees with this selection or if you know of a better one.

Being an engineer, I made some actual before and after measurements using a Kestrel 4000 anemometer. Prior to installing the new blower, I measured approx. 1200 fpm (feet per minute) of airflow coming from the center vent with the fan set on it's highest level and the A/C set to "MAX". I say approximately because the value did vary by as much as 35 fpm as I was holding the instrument. The attached picture shows an actual reading, including the temperature of the air blowing from the vent.

After replacing my old blower, which I am absolutely certain was the original blower from 1980, I did measure higher flows coming from the center vent on the order of ~1350 fpm which represents a 12% increase in volume. There was no measurable difference in temperature however.

If I had not measured the difference, I am not certain I would have been able to physically detect any change, which makes me suspect perhaps I didn't buy the correct new blower. But given the low cost and ease of changing the blowers, I still think it was well worth the time and money for even a 10% increase. From what I've read after searching older threads, many others have reported a much greater change after making the swap. I think one explanation is that undoubtedly the blower in some folk's trucks have aged worse than others.

Overall, I'd heartily recommend making the swap. Even if you don't detect a great change, it is probably there and working to your benefit.