Start with the error this page is built to stop: taking a cubic-inch figure and dividing by 1,000 to get cc. That is the litre move, and it is wrong by a factor of about sixteen. A cubic inch is 16.387064 cc, so a 350 (349.85 CID) is roughly 5,735 cc, not 0.35 of anything. Get that constant right and cubic-inch displacement becomes simple; get it wrong and every conversion downstream is off.
Calculating CID from bore and stroke
Work entirely in inches: π ÷ 4 × bore² × stroke gives cubic inches per cylinder, and multiplying by the cylinder count gives total CID. The classic small-block V8 — 4.00-inch bore, 3.48-inch stroke, eight cylinders — comes out at 349.85 cubic inches, which the market rounds to "350". No unit juggling is needed as long as bore and stroke are both in inches.
The exact reference chart
American engine names are nominal; the geometry is what the calculator reports. Here is how the familiar badges resolve when you do the maths honestly:
| Engine (nominal) | Bore in | Stroke in | Cyl | Exact CID | Litres |
|---|---|---|---|---|---|
| Chevy 283 | 3.875 | 3.00 | 8 | 283.0 | 4.64 |
| Chevy 302 (DZ) | 4.000 | 3.00 | 8 | 301.6 | 4.94 |
| Chevy 327 | 4.000 | 3.25 | 8 | 326.7 | 5.35 |
| Chevy 350 | 4.000 | 3.48 | 8 | 349.8 | 5.73 |
| Chevy 383 stroker | 4.030 | 3.75 | 8 | 382.7 | 6.27 |
| Chevy 400 | 4.125 | 3.75 | 8 | 400.9 | 6.57 |
| Chevy 427 (BBC) | 4.250 | 3.76 | 8 | 426.7 | 6.99 |
| Chevy 454 (BBC) | 4.250 | 4.00 | 8 | 454.0 | 7.44 |
| Ford 289 | 4.000 | 2.87 | 8 | 288.5 | 4.73 |
| Ford 302 | 4.000 | 3.00 | 8 | 301.6 | 4.94 |
| Ford 351W | 4.000 | 3.50 | 8 | 351.9 | 5.77 |
| Ford 460 | 4.360 | 3.85 | 8 | 459.8 | 7.54 |
| Mopar 340 | 4.040 | 3.31 | 8 | 339.4 | 5.56 |
| Mopar 360 | 4.000 | 3.58 | 8 | 359.9 | 5.90 |
| Mopar 440 | 4.320 | 3.75 | 8 | 439.7 | 7.21 |
Notice how a 4.00-inch bore serves several different engines — 302, 327, 350, 351 — with only the stroke changing. Stroke does the heavy lifting once the bore is fixed, which is the whole idea behind a stroker.
Why a small overbore adds cubic inches fast
Because volume scales with bore squared, a rebore that sounds tiny still adds measurable displacement. Going 0.030-inch over on a 350 lifts it by roughly 5 cubic inches — you are enlarging the squared term, not a linear one, which is why builders take overbores seriously even at thirty thousandths of an inch.
Turning CID into cc and litres
The panel shows all three units at once, but the moves are worth knowing. Cubic inches to cc: multiply by 16.387064. Cubic inches to litres: divide by 61.024. So a 454 big-block is about 7,440 cc or 7.4 litres, and a 302 Ford is about 4,942 cc or 4.9 litres. The constant, not a rounded 16.4, is what keeps a big-block's figure from drifting by a cubic inch or two.
Nominal versus measured, and why it matters
For a stock engine, published bore and stroke give a reliable CID. Once a block has been bored oversize or has worn, use the measured bore — a 4.030-inch cleaned-up 350 is a few cubic inches larger than its 4.00-inch nominal, which can be enough to move a displacement class. The tool's Build precision mode shows the extra decimals machinists work to.
References & standards
- NIST SP 811 — Guide for the use of the SI, including the exact inch and unit-conversion factors.
Frequently asked questions
How do I calculate cubic inches from bore and stroke?
Use π/4 × bore² × stroke with both in inches for cubic inches per cylinder, then multiply by the cylinder count. A 4.00 × 3.48 V8 comes out at 349.85 CID.
Why is a '350' actually 349.85 cubic inches?
Because the badge rounds up. The real 4.00 in bore and 3.48 in stroke across eight cylinders geometrically give 349.85 CID, which everyone calls a 350.
How do I turn cubic inches into cc?
Multiply CID by 16.387064. So 350 CID is about 5735 cc; the panel shows the cc and litre equivalents next to your cubic-inch figure.
Should I ever divide cubic inches by 1000?
No — that is the litre conversion for cc, not for cubic inches. Dividing CID by 1000 is a classic error; use 16.387064 to reach cc first.
What is a 383 stroker in cubic inches?
About 382.67 CID from a 4.030 in bore and 3.75 in stroke — a 350 block bored slightly and given a longer-stroke crank.
How do I get litres from cubic inches?
Divide CID by 61.024. A 350 is about 5.7 L, a 454 about 7.4 L. The litre figure appears automatically beside your result.
Do I use nominal or measured bore for CID?
Measured, once an engine has been bored or has worn. A 4.030 in bore adds a few cubic inches over 4.00 in — enough to move a class.
Why does a small overbore add cubic inches so fast?
Because volume scales with bore squared. Going 0.030 in over on a 350 adds roughly 5 CID, because you are enlarging the squared term, not a linear one.
Is CID the same as cu in and in³?
Yes — cubic-inch displacement, cubic inches and cubic inches are three names for the identical unit. The tool accepts and shows all three spellings.
What bore and stroke make a 400 small-block?
A 4.125 in bore with a 3.75 in stroke across eight cylinders gives about 400.9 CID, the classic small-block 400.
How accurate is the cubic-inch result?
Exact for the inputs, because it uses the true 16.387064 constant rather than a rounded one, so it stays reliable for class checks and machine planning.
Can I check what class my CID lands in?
Yes. The panel names the closest common engine and displacement band, so a cubic-inch build immediately reads across to a familiar size.
Does the tool handle big-block dimensions?
Yes — up to a 16-cylinder count and any realistic bore, so 427, 454 and 460 big-blocks calculate the same way as a small-block.
Your recent calculations
Stored only in this browser.