Have a 92 Roadmaster Limited, stock Delco Autoreverse with very weak, noisy
AM. The car has an auto-raise/lower mast antenna in the rear quarterpanel.
FM does pretty good, pulling in 25kW stations from 40 miles away quite
easily. AM is another story. I get a lot of noise over even 50kW stations
while driving in the same city. Since FM is strong, I will assume the coax
and antenna are okay.

I remember the "old-style" Delco radios that looked like this --
o HHHH o
had a tuning capacitor located near the tuning dial for matching the
antenna to the radio. Do the newer type have an antenna matching cap on
them? If so, where is it located?

Thanks.