more slant six timing q's

If you used the early harmonic balancer on a later engine, the timing mark will be off by quite a bit. You'll need to find out where true top dead center is and then set the timing accordingly. You can do it by screwing a long threaded (same as the spark plug) bolt into the #1 plug hole and rotate the engine BY HAND until the piston just hits the bolt. Make a mark on the balancer where it lines up with TDC on the timing mark. Rotate the engine the opposite way BY HAND until it hits again. Make another mark on the balancer at TDC. Half way between them will be true TDC on the balancer. If it doesn't line up with the balancer notch, you need to get the correct balancer that does or remark the one you have. If it still pings you may have to back off the timing a bit until it stops but do not go into the after top dead center zone. Performance and mileage will suffer and
the engine will probably run hot. If it still pings at 0, you'll need fuel with a highter octane rating.