My 1970 250C makes a klunking noise on acceleration.
It's coming from the rear of the car & continues up to about 40 m.p.h.
Once I get up to cruising/highway speed (above 40) the noise goes away & the car rides smoothly.
I suspect the center driveshaft support bearing.

Does anyone have any other ideas?

Also, is it dangerous to drive it like this?

Thanks!