# 400 engine question



## pony462 (Oct 29, 2015)

I have a '67 YZ 400 engine that has been bored 60 over a 455 crank cut for
the 400 and stroked. Can someone give me an idea what my CI displacement
Might be? This is all I know about this engine.

:smile2:


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## BearGFR (Aug 25, 2008)

455 crank, if otherwise nominal (not offset ground or anything) will have a 4.21" stroke. +0.060 400 means you're running a bore size of 4.180.

Simple math: Area of 1 cylinder = 3.141592 * (4.180/2)^2 * 4.21
(pi times radius squared times height)
times 8 (for 8 cylinders)
works out to 462.184 cubic inches.

Bear


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## oldskool (Apr 26, 2015)

Or, if you are not a math whiz, you can just plug 455 + .030(since the 455 had aprox .030 larger bore size than a 400) into the Wallace Calculator and it will also give you 462 cubes. 

Compression Ratio Calculator - Wallace Racing


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## pony462 (Oct 29, 2015)

Thanks Bear & Oldschool that really helps didn't think it would be that much. The math looks much easier the way you explained it.
Thanks again


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