Bad Radio or A Voltage Issue?

[gtp3.8]

Hello I am new to the Mustang forums. I have been reading over some of the old posts and I feel like I maybe I have narrowed this down to one of the two problems. I have a 1991 LX with the 5.0 5 speed. It does have a small cam and other supporting mod incase that would be of any revelance to the issue. This problem seems to happen more at night than any other time. Whae I come to a red light or stop sign and start to take off my radio cuts out but when it comes back on all of the settings are still in place Base Treb ect. My volt meter gets about a mark and a half from the bottom red mark but ones I get to going it will pick back up. I just monday put a new altinator (factory size) on it and same problem thought it does have a higher charge now while running. Last night when I parked in the drive way and let it idle the radio would play but when I would flip from low beam to high beam it would cut out. I know that the alt pulley is factory size but im not sure about the crank and water pulleys. Im going to check those when I get off. Does this sound like a charging problem or a radio or wiring problem? Thanks for any help or advice.

Justin

[HiFlow5 0]

Do you have an aftermarket radio or is this a stock one? I'm going out on a limb here and going to say it sounds like a faulty wiring job of some sort.