Here you go, Piston area and force.

I think there a few here that get it, but not the dummies '273' & Turk. I will post the info AGAIN from Harold Bettes, who does get it. [ Turk read the text, don't look at the pretty pictures ] What does Bettes get? He gets that if you increase piston area, the pressure loading over area [ using pounds per sq in as an example ] becomes less. Pressure has become confused with force.
The formula below, uses simple everyday words, is very simple.....& even the dumbest of the dumbest should be able to 'work it out'.

Totally agree that a bigger diam piston can make more hp. [ So does a longer stroke ]. What pushes the piston to turn the crank? Doesn't do it by itself.......????????????

Making it simple: the piston draws air into the cyl by creating vacuum as it goes from TDC to BDC. If you make the piston BIGGER, you are pulling more air through the same size valve opening, & that creates more vacuum..........so more air has now filled the cylinder. More hp is created because more air is drawn in to be compressed. A bigger diam piston does not guarantee more HP by virtue of it's area. Chrysler proved it!!! They made an odd ball 383 engine that was a raised block engine, not the more common low block 383. Not used by Dodge & Plym, Chrys only 1959 to 1961.
Bore/stroke RB 383: 4 1/32 by 3.75
Bore/stroke LB 383 4 1/4 by 3.38
Both engines had 10:1 CR. Both made exactly the same hp/tq: 325/425. But, but, but, but LB 383 had a bigger piston....shoulda made more hp. Huh?

Here is the formula again for HP related to piston area:
Unless you are particularly dumb, it should be obvious that the HP/to area gets less as piston area gets bigger because piston area is on the bottom line of the formula

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