Pinging on acceleration.
Remember back in the 60’s regular gas was 95 octane .
No, in the '60s regular gas was 91 octane, by the RON method (Research Octane Number).
Other parts of the world still post RON on the pumps, but since the '70s in North America, we use the AKI method (Antiknock index), which is the average of the RON and the always-lower MON, Motor Octane Number. Today's 87-octane regular has a RON of ~91. That is: the same antiknock performance as the pre-1970s regular gasoline labelled "91".
So today you should be using premium 93 octane and setting the timing for it .
No, a stock or near-stock Slant-6 runs well on regular (87, by today's numbers). There is no benefit to running high-test gasoline in a stockish Slant-6, but there is also no drawback—except to the wallet. High-test doesn't burn slower, it just more strongly resists spontaneous combustion (detonation, ping, knock…). Higher-than-87-octane gasoline is a waste of money. Yes, you can tune the engine with some more advance and get a bit better fuel economy if you run high-test, but the math doesn't come close to working; you still wind up spending a lot more than you save.
Leaded gas was for valve seat wear
Primarily it was a cheap way of raising the octane of gasoline. It also
buffered the exhaust valve/seat junction, so automakers didn't have to harden the seats or specify higher-grade valves, thus saving them money.
today you have two choices , run hardened valve seats or a gas additive with every tank .
The Slant-6's exhaust valves are small, and the seats well-cooled. A pre-1973 Slant-6 (no hardened seats) in typical service will last a good, long time before there's any valve seat recession; when that eventually does happen, that's when you have hardened seats put in. Additives of this claimed nature are a waste of money twice: first when you buy them, and then when they crud up your spark plugs a whole lot faster in exchange for no practical benefit.
Also you have two choices when it comes to motor oil to keep your non roller cam and lifters alive , run hot rod motor oil that has ZDDP in it or add ZDDP to modern oil with every oil change .
This is
also false. Yes,
really.