351 plus .030 bore = ??cid

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Feb 13, 2008 | 02:10 AM

honkytonk

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From: New Orleans--High Ground

351 plus .030 bore = ??cid

just had my 351 machined to .030 and was wondering what the new cubic inches were gonna be? Ive searched this forum for half an hour and cant seem to find the answer.

thnks

Feb 13, 2008 | 02:55 AM

bucks77ford

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From: Kasson, Minnesota

I was thinking it would be 393 CID. Use the formula:

Bore x Bore x stroke x # of cylinders x .7854 = engine displacment

4.030 x 4.030 x 3.850 x 8 x .7854 = 393 (rounded)

Last edited by bucks77ford; Feb 13, 2008 at 03:00 AM.

Feb 13, 2008 | 05:57 AM

fastfarmer

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From: southwest Wisconsin

351 has 3.5 stroke. 3.030 X 3.030 X 3.5 X 8 X .7854 = 357 cu in

Feb 13, 2008 | 06:02 AM

brownfoot

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something's wrong with your formula
4 x 4 x 3.85 x 8 x.7854= 387 cu. in........................not 351??????

Feb 13, 2008 | 07:49 AM

fastfarmer

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From: southwest Wisconsin

My post above should read 4.030 X 4.030 X 3.5 X 8 X .7854 = 357 cu in.

Feb 13, 2008 | 11:35 AM

pdqford

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From: Central NYS

Common guys - volume of a cylinder is pie times radius squared times height.

4" bore has a radius of 2", pie is 3.1416.

So one cylinder = 3.1416 times 2" times 2" times 3.5 = 43.98 cu in

times 8 cylinders = 351.86 cu in.

A .030" over bore would change the radius to 2.015".

So one rebored cylinder would be 3.1416 times 2.015" time 2.015" times 3.5" stroke = 44.64 cu in. times 8 cylinders = 357.16 cu. in. total displacement.