I used these instead of stock on my 1966 520. Not sure if they are legal where you are. These are DOT approved and only draw 10 amps each on brights turning on and 5 amps each continuous. No, stock wiring changes needed, but I would go ahead and wire in relays for at least the high beam circuit and another for the low beam circuit. These are glass faced and closely match the curvature of the stock sealed beams. I would order an extra set of replacement bulbs other than the Hella's as the Hella's seam to not last long. Also your stock headlight plugs, plugs into these bulbs. I am using my stock wiring and plugs, but I have not actually run these lights using the stock Datsun plugs. I might set up a test with these lights and let them run say 8 hours on high beam and see if it melts the stock plug. I will edit this post after I run this test.
My 520 light buckets with the Hella's installed