I'm looking at H4 headlights and bulbs as an upgrade for my '72. What is the brightest legal headlight? I see bulbs that range from 60W high beam/55W low beam to 130W high beam/90W low beam.

You might be interested in putting in a relay after reading this.........
http://67-72chevytrucks.com/vboard/showthread.php?t=182351&highlight=headlight+relay

I forgot to mentioned that I've just added the relays.

Now I'm wondering what H4 headlights to buy that will still be DOT legal?

60/55 is the legal limit, but for a few years I had 85/65 if I remember right. I had my truck lowered 5" in front and just had them aimed a bit low and never had a problem. Only occasionally did someone flash me.

I had 55/100's a few years back and I had no problems.

I've got 100 watt highbeams, and 85 watt low beams in my 77. I have European H4 lenses, and upgraded wiring, relays, and a 105 amp CS alternator.

The highbeams are intense, but the lowbeams light distribution is aimed in such a way that I never get highbeamed unless I don't dim my lights fast enough (gotta be quick, cause the 100 watt highbeams are VERY bright).

Infact, I had my sister drive my truck the oppsite way while I drove her car, and my low beams looked dimmer than most other halogens out there! You could tell they were on, but there was no major glare. Lights up the road better than my old highbeams used to though :)

With incandesent bulbs, I believe the legal limit has been 55/60. However, I'm not sure if the legal limit is measured in wattage anymore, especially with the rise of LED and HID lighting. It's probably measured in lumens.

Actually, here is a pretty good article...

http://en.wikipedia.org/wiki/Headlight

I personally just got the diamond cut 7" round H4 bulbs with built in projectors for my '70 K20.

I was looking at this one:
http://store.summitracing.com/partdetail.asp?autofilter=1&part=GRM%2D09%2D121&N=4294887656+4294908390+4294906058+115&autoview=sku

Is there an advantage to the diamond cut?

I was looking at this one:
http://store.summitracing.com/partdetail.asp?autofilter=1&part=GRM%2D09%2D121&N=4294887656+4294908390+4294906058+115&autoview=sku

Is there an advantage to the diamond cut?
looks maybe

These are the ones I just got:

$35 for the pair, shipped with all of the necessary bulbs. The H4 bulbs are 55/60W.

7" round diamond cut euro lights with halos (angel eyes), city lights, and projector center. I think I might change the small blue city light into an amber turn signal. We'll see.

"Symauto" is the ebayer that I bought them from, if anyone is interested.

Now I just have to get those relays - heheh.

http://www.symmicauto.com/images/auto/4515.jpg
http://www.symmicauto.com/images/auto/4515-2.gif

Another options for bulbs are motorcycle ones. They have lots of different wattages. I use one for a Honda black bird on 2 of my converted trucks. 55/115 don't need driving lights with those