1979 Model G20 Van & Halogen Headlights

The older standard headlights for this year are not readily available at any parts store, in which, I've been very disappointed with their brightness for some time and would very much like to go with the upgraded halogen that are 50% brighter, and have the same plug set-up. The van has the heavy duty alternator but do not want to assume this is the only issue that must be considered going forth with the upgrade.

If this is not a viable solution or even is, what brand of driving lights give the best bang for the buck?

Thanks

Use the halogens. They do not use more power, just make more light (they're more efficient).