Car Stereos: new Install shaft style car radio, shaft style, 67 chevelle

Question
I have a 67 chevelle took out am radio and installed an aftermarket shaft style am fm cassette radio I had to connect all wires  it works great when car is not running,but when I start the car there is a loud buzzing on radio and cassette I can hear music but noise in background is loud

Answer
Ted, that is a common problem on old cars.  It is the charging system sending power up the power wire.  There are two fixes for the problem.  First, use a larger wire for your ground, and attach it as close as possible to the radio.  A really short ground makes the circuit as short as possible.  Second, they make a noise filter that goes inline of the power wire to filter out the extra charging noise.  If the short ground doesn't solve the problem, then add the noise filter, and it should take of the problem for good.  Hope this helps, Scott