Originally Posted By: 901Memphis
It has a shield over the low beams but slits in it.
I'd probably not do it in those housings either. The slits in the glare shield can be problematic, and the optics probably aren't ideal, either. GM used very small lamp buckets back then...the physical size of the reflector is quite small. These smaller reflectors just don't do as good of a job of beam control as a larger reflector can. That's logical, too...imagine slowly shrinking that reflector smaller and smaller; eventually, all definition in terms of shape and angles will disappear. And conversely, imagine growing it larger and larger and you can add more and more definition and refinement to the "prisms and mirrors".
Compare how "simple" in terms of design your Buick's lamps are compared to much larger ones, such as from a newer Dodge Ram:
Here are the ones on a CR-V for another comparison, though it does take a different bulb design:
Don't get me wrong; I'm not saying that HIR2 is hands-down not a good idea. I'm saying that older optics don't have as much glare control as today's cars do, and that it MAY not be appropriate. The HIR2 offers a nice improvement in lighting at the risk of increased glare. Newer optics control glare so well that the increase is often not substantial (because an 87% increase in a very low amount of glare is still a low amount of glare). An 87% increase in a low-to-moderate amount of glare can be problematic.
With these older lamps, my personal recommendation is to stick with an HB4.