BOTTOM-END MATH // NO MORE FORUM GUESSING
Piston & Rod Calculator
Pick what you're shopping for — block, crank, rods, pistons, head, gasket — and see exactly where the piston lands: deck clearance, compression estimate, rod/stroke ratio. Buy once, mock up never.
The shopping list
Presets use published figures — verify against the piston card and a burette before you cut metal.
The math, in the open
Deck clearance
Block deck height − (half the stroke + rod length + piston compression height) — how far the crown stops below the deck. A negative number means pop-up above it.
Compression estimate
Swept volume + clearance volume, divided by clearance volume. Chamber, gasket, deck and dome all count — that's why guessing fails.
Rod/stroke ratio
Rod length ÷ stroke. Higher revs easier on the walls; lower makes grunt but loads the skirts.