For more than 70 years ZDDP (Zinc Dialkyl Dithio Phosphate, containing Zinc and Phosphorus) was a mainstay of motor oil, providing trouble-free engine protection. The E.P.A. has now forced most ZDDP from domestic motor oil, including diesel oils. This lack of zinc and phosphorus is most severe in the just-released 'SN' (ILSAC GF-5) rated oils

Mobil 1 V twin is probably one of the best oils going. Exspensive, yes, but you said the best.
Amsoils. Dominator is also a very good choice.

I looked up the Amsoil and it says it has high amounts of zinc and phosphorus

Joe Gibbs Racing Oil..

Dyno Proven And Lowered My Oil Temps A Lot..

As per Amsoil web page...

Dominator Synthetic Racing Oil’s superior additive technology provides unmatched durability in extreme conditions. In addition, its high levels of zinc and phosphorus additives make it ideal for street rods, muscle cars and other vehicles with flat-tappet cams.

Watch out with that V-Twin stuff also.

I have seen roller lifters and even roller rockers with flat spots.

JOE GIBBS OR AMSOIL both very good use on 1075 over 75hrs

Running at 5,000 rpm with about 2 hours on new oil change. The oil pressure drops to ZERO, I try to turn off engine a quickly as possible.
Tare down.... the oil pump pick up tube broke off. Pistons, rods, crank were all OK! Surprised everyone. The oil was SWEPCO.

Running Bradd Penn 20w-50 and wix racing filters. Welded my oil pickup on tho. Hope the filters are still as good as they used to be.

don't waste your money on synthetics, any name brand 15W-40 will work just fine.

any name brand will work if it is not SN rated......

Valvoline VR-1 racing 20-50, Merc Filter.