i've never actually seen the difference of the two in person, but is there anyway you can make a h4 bulb fit a h4h socket (jdm ef headlight)....kinda like the 9005/9006 conversion?

 

Yeah, there are a few ways. One way is to take a dremel and file down the edges and make three prongs yourself. I used this method to retrofit Lexus oem HIDs into my h4h siR headlights. Just look at the pattern inside the headlight and match that. Good luck

 

yep just do some cutting and they work fine.