figuring out cubes

[theautomatics]

Hey I'm trying to figure out how many cubes I'd have after stroking a 302 (like a 331) 2.25 I think with a small bore of 4/100th. Is there a way to figure this out?

 

[D.Hearne]

Bore radius X bore radius X Pi (3.1416) X stroke X number of cylinders. Radius is half the bore diameter.

 

[iapexl8r]

http://www.fordmuscle.com/calculators/compression.shtml

 

[BlownFiveLiter]

I prefer the formula: bore x bore x stroke x .7854 x the number of cylinders, to calculate displacement. Quick and simple.

 

[69gmachine]

Hey Auto, stroke on a 302 is 3 not 2. A 331 is normally 4.03x3.25 when starting with a used production block.

Dividing by 2 twice is really such a pain. I can see why StangGT1995 would rather use the much simpler formula.

Just bustin' your chops Stang man... hope you don't blow a gasket!

 

[BlownFiveLiter]

Nah, no gaskets blowing here. I believe the formula I posted above is the same one the NHRA uses to calculate displacement.

 

[theautomatics]

Ok thanks for that BUT. I'm using a brand new Boss 302 block. Does that allow a bigger bore? Basically the guy working on my engine goes "well since it's a 302 boss block we can get a lot more cubes than a 331. Is he implying go with a 347? Does the boss block allow a larger bore?

 

[D.Hearne]

The new Boss block can be bored to 4.125.(plus another .030 or so) Combine that with a 3.25" stroke and you've got a short stroke 347. Go with a 3.4 crank and you're up to about 370 cubes. Ford's new crate 331 is a 4.125 bore X 3.1 stroke crank.

 

[theautomatics]

thanks a metric ton. Would a bore of .125 over be pushing the limits on the walls?

 

[D.Hearne]

No, that's what that block was designed for---4.125" bores.