How much weight did all that sound deadening add? I thought about doing that on my '70 Duster but I don't really drive it very long distances (over 100 miles) much anymore and the car is gradually becoming more track-oriented. Main reason I don't drive it a lot though is due to the road and wind noise, cruising at 80 MPH gets tiring pretty fast. Overdrive to slow the engine down at cruise would help but the wind and road noise are awful.
I have the same issue described above, I have some aftermarket speakers in the doors and rear package tray with a very old but working tape deck and I have to crank that thing up LOUD to hear it over all the noise on the freeway.
