Headlight dust cap?
 

Does anyone know what size headlight bulb dust cap we need? Ya know, the rubber seal that goes around the bulb to seal the headlight?

I'm gonna do a retrofit and need to know what size extended cap to buy. Thanks

I am not sure exactly what you are talking about; but you might try browsing an on-line parts retailer such as tascaparts.com to see if you can find it