I have a 67, with a 383, 4spd Muncie and 4.11 read end.
I have only had the car a year. I have noticed in the past that when cursing in 4th gear, if I give it more gad than just easing into it, I would hear this violent metal clanging together sound from maybe the bell housing area. Then, I noticed today that when driving a a much slower speed and very low rpm’s I went to give it a bit of gas and I heard the same but, obviously just not quite as violent.
It doesn’t feel like the transmission is slipping but, I could be wrong. Any thoughts?