I ran 60/55 watt H4 low beams and H1 55W high beams in the Challenger for several years with nearly stock wiring (only the main feed wire to the ammeter was replaced, bypassing the bulkhead connector; I hadn't done the relay job at the time). It worked fine with low beams, but trying to use high would start cycling the headlight switch circuit breaker. I don't doubt I got less light out of it than I would have with relays but it was still a vast improvement over the old tungsten incandescent.