What is the procedure for adjusting the antenna for best reception for the AM-FM stereo radio? The car is a 1978 Coupe. 

Tune the AM dial to a fairly strong station near 1400. Then pull off the tuning knob and round trim piece surrounding it. You should see a small screw above the tuning shaft. With the radio on, use a small screwdriver and turn the screw until you get the strongest signal from the radio station it's tuned to. Then you're done...just reinstall the trim and knob and your radio is trimmed.

Thanks for the help. I'll do it this evening. What is resistance of the speakers. My speakers are really sounding muddy. They are original and need to be replaced. Any suggestions of what speakers to put in?

Ive replaced the speakers in both my vettes. The first one (74) I bought speakers when I had the radio rebuilt from the company that did the work. He had speakers that were as he said "better quality and more ohms". The 72 I just bought the standard vender speakers when I bought the aftermarket radio from Ecklers. There is a huge difference between the quality. The ones from ecklers sound like they are in a fish bowl and have no real volume. The ones from the radio rebuild are much better and didnt cost but a dollar or two  more. I hate to do this but I plan on buying another set and removing the dash and replacing them again. I should have known better! I'm not home until Wednesday but if you are interested I can look up the shop I bought the good ones from. Just PM me if interested.
Rodney

Lynn
The company I bought the better speakers from was S & M Electro-Tech, Inc. 877 780 2861. Give them a call. Hope it solves your problem with bad speakers.
Rodney