Halogen bulbs will be brighter than the original tungsten bulbs. Modern HIDs or LEDs are better still.
However, halogen bulbs have their filaments in different places in relation to the bulb mounting flange. The original reflector was shaped to put the light from the tungsten bulb in the right place and beam pattern. Whilst conversion bulbs try hard to get them as close as possible to the originals, it is not possible to get them absolutely right. Results can be variable. Bulbs have numbers, used worldwide. The standard H4, twin filament halogen bulb is a 472. The most popular tungsten before these was a 410, with a fat round bulb and a large round mounting flange. There used to be conversion bulbs, usually numbered 2983. These usually gave lots more light, but mostly spread around in the wrong places, and were often no better when driving at night. The DAF cars I used a long time ago used Cibie headlamps and were actually better with a 410 than a 2983. As the bulbs dim with age, replacing these annually proved better than just blinding everyone else with bright light.
Many people were pleased with the conversion bulbs, but not usually the people coming towards you.
If you can find replacement lights, designed for halogen bulbs, that would be the ideal way to go.