Headlight conversion?? Help!

So I have a 86 b2000, and I was thinking about converting to either a HID or a LED, but I was thinking, if I was to get the Hella H4 5x7 light housing would that fit in my truck so I could change the bulbs and do the job properly?

Certain bulbs work better with certain reflectors.

the 5x7 is smaller then the stock lights, stock is the 7" lights.. 7x6

stock is 7x5 isnt it?

I can never remember what size they are...

Yes, they're 7x5.