There's no reason to convert to 12V other than to install power windows, seats door locks, air conditioning etc. If you want modern sounds you can by a converter for it for a lot less trouble than converting the whole truck. Or use a Walkman or Ipod.

"It's just a phase. He'll grow out of it." Mama, 1964

1956 Chevy 1/2-ton 3100
1953 Chevy 6100 "The Yard dog"
1954 GMC Suburban Now with a new proud owner.