Blower noise..?

I haven't used, listened to or been exposed to a 52 year old heater in 30 years...I'm use to the modern cars and the climate control, whisper quiet heaters, etc.. The reason I ask is, in my non running project I have everything back together in the interior after it was all torn out and while checking the wiring I turned my heater on and the blower seems to make a "noise" on low and gets faster when turned on high.. Kind of like a clicking noise.. Hard to describe exactly what I'm hearing..to the point of wondering if it's normal, 50 year old tech, or if there's an issue. Maybe I can post a quick video /sound bite of what I'm talking about..
I will say it almost sounds like something that if you tapped on it with a rubber mallet it would "fix" it... If that makes sense...
72 Demon non A.C
New video by Jo69 Ha69