6v halogen sealed beam headlights shine as bright and as far as the lights on any modern 12v vehicle.
If you have modern 6v Sylvania, Wagner, or Philips halogen lamps, and they're dim or dull, you need to examine your wiring. Make sure the lighting circuit and the rest of the truck is perfectly grounded.
You also need to make sure they're aimed properly.
1950 Chevrolet 3100 (Ol' Roy)
1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)