The original housings are designed to the focal point of the bulb element. Engineering in some other light source that does not match the exact geometry of the original bulb may or most likely will not produce what you desire.
Our pusher has the large Par56 round sealed beam incandescent headlights, similar to what you see on older Jeeps. I changed these to multiple led assemblies with integrated running, turn, high and low beam. They look nice, fancy is a better description, but I still installed additional driving lights to be compatible with the average lighting system on today’s vehicles.
Good luck