Not much out there in 4” bulbs that fit the o/e housings except high buck LED units. Me, I don’t like multi facet LED bulbs.
You could go with the rectangle Shelby type fogs but I have no info on their performance.
NPD has a tri bar bulb that looks good but again unknown performance, I guess you could call them and ask.
Good luck.

With a little effort, you can make PAR30/36 sealed bulb fit into the fog housing. These are sold in any watt range from 100 - 300 watts and also have 12v ones. Look into a pool market or stage lightning because that's where thay are used mostly. They come in spot/wide and ultra wide beams.

Put a pair into another brand car which had to pass a forrest every night and they were more then bright. DON'T touch them, very hot they are! Don't remember exactly what i did to put them in but it was an easy job for sure.

Mustsed

Mustsed wrote:

With a little effort, you can make PAR30/36 sealed bulb fit into the fog housing. These are sold in any watt range from 100 - 300 watts and also have 12v ones. Look into a pool market or stage lightning because that's where thay are used mostly. They come in spot/wide and ultra wide beams.

Put a pair into another brand car which had to pass a forrest every night and they were more then bright. DON'T touch them, very hot they are! Don't remember exactly what i did to put them in but it was an easy job for sure.

Mustsed

Just a word of caution, if you use bulbs that are 100 watts each, you'll being drawing like 15 amps for two lamps, at 300 watts it would be about 45 amps.  Any wiring, relays, switches, connectors, etc. will need to be able to support that power. 
 

My headlights are super bright after installing relays.  I think the fog lights were for decoration only.  They are whimpy.

6Sally6,

It rarely gets foggy in Texas;but, some of the bash trips require night driving to the restaurant, and since I am unfamiliar with the streets I like the advantage of lots of light.

I wish I just had some in my grille.