Texas Trans Am Service and Restoration

This online calculator is designed to estimate the change in compression ratio due to a change the cylinder wall bore.

Enter the Stock Cylinder Bore Diameter, the amount that the bore in increased, the stroke length. Click the Calculate Compression button for results.

Stock Cylinder Bore Diameter:	Inches
Cylinder Over Bore:	Inches
Stroke Length:	Inches
Head Chamber:	CCs
Gasket Thickness:	Inches
Deck Height:	Inches
Piston Dish:	CCs
Number of Cylinders:

Stock and New Bore Diameter

	Stock	New Bore
Cylinder Bore Diameter:	Inches	Inches
Displacement:	Cubic Inches	Cubic Inches
Compression Ratio:	to 1	to 1
s/n bore radius
s/n radius square
s/n area bore (Pi r2)
S/n total Cylinder volume
extra volume Cubic Inches

Pontiac	Bore	Stroke
265	3.75	3.00
287	3.75	3.25
301	4.00	3.00
316(317)	3.9375	3.25
326	3.718	3.75
'63 "326"	3.781	3.75
347	3.9375	3.5625
350	3.875	3.75
370	4.0625	3.5625
389	4.0625	3.75
400	4.12	3.75
421	4.09375	4.00
428	4.12	4.00
455	4.151	4.21

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"Restoring Old Dreams"

Owner and Operator, Mr. David Mars
Serving the community since 1991
Email: david@texastransams.com
4588A Kennedale - New Hope Rd.
Fort Worth, TX 76140
Phone: 817-563-2121