Cooling Fan Replacement
I started a separate thread about reducing the interior sound level in the cab.
http://67-72chevytrucks.com/vboard/s...d.php?t=839201
One of the board members suggested that I replace the flex fan (installed by the previous owner) with a clutch fan. Flex fans are notoriously noisy, and this one was no exception.
I had a 7 blade fan on-hand from a long ago project, but the clutch was sized to fit an Oldsmobile water pump. So, I made a trip to my local O'Reilly for a Chevy clutch. I also had to replace the extended fan bolts that came with the flex fan back to factory studs. I happen to have a set of those on-hand from an old project too. Let's hear it for parts hoarding!
The installation was pretty simple. It didn't lower the actual decibel level inside the cab, but did change the "roar" of the engine in a positive way. On a test drive, the temperature stayed right where it was with the flex fan and it was less offensive to the ears. We'll call it a win.
Cooling Overflow Tank Replacement
The previous owner installed an off-the-shelf plastic Dorman overflow tank. It worked, but it was ugly. So, I replaced it with an aluminum tank I picked up for a few bucks on Amazon. The aluminum tank is no more "original" than the mid-'70's Dorman plastic tank, but it looks a whole lot better. Someday, I may clean up the engine bay by relocating the tank in front of the radiator, but this will do for now.