I have a 68 OHC-6 with a TH-350 (chevy) trans behind it. When I get the car going about 35 mph, I get a resonating sound inside the car. It almost sounds like the bass from a boom box in a car next to me. The sound goes away at speeds above or below approx 35 mph. I do have sound deadening material on the entire floor pan.
Any ideas or anyone else seen or heard this problem?
