You have spent lots of hard earned money and TONS of time restoring your old motorcycle or classic car so why not spend a little and protect your valves and cams? That's what the ZDDP debate comes down to. It's not even a debate. Old fuel was SO much better than the thinned down alcohol crap we are buying today. You need to prime your fuel and oil with a little ZDDP additive so that you restore some of the lubrication qualities.
I have more information and more links than you might care to read on my thread:
My Thread & Link on ZDDP