90psi on a 3.91 bore is 1081 pounds of force...
this is why cranking cylinder pressure of 180psi, in a 3.91bore, (2162 pounds of force), makes such a sweet street engine. And a tired old 318 with 90psi is a total dog of an engine.
And that is also why a 268* cam in a 318 is such a POS off the line with a stock TC and 2.76 gears; it's the abysmal amount of motive force. At 120psi, it amounts to just 1441 pounds of force.... compared to the stock smogger-teen at 140psi having 1681 pounds of force. So you have to wait, and wait, and wait, for the engine to get up to some rpm where the engine-combo starts trapping air. With 2.76s, it's a really, really,reallyyyyyyyy long wait.
But at TDC in a static engine,90psi means nothing, cuz the crank ain't moving. But if it moves just a little, in the blink of an eye it will be headed down to BDC, and there won't be a single thing you can do to stop it. Lord help you if it goes over backwards with you hanging onto the breaker-bar.
But it's a pretty handy way to undo the balancer bolt, if it goes the normal way, and doesn't tear your arm off on the way down.
