Quote: stroke a 413 to a 4" stroke making 439cid (yes i know custom pistons blah, blah, blah). the way smaller bore 413 will make more horsepower & torque then the larger bore 440. thats a guarantee"
Quote: and the self proclaimed gurus crack me up as well. prove me wrong. if you think you get the same hosrepower from a 4.32" x 3.75" vs 4.18" x 4.00" bore and stroke 440 cid engine your sadly mistaken my friend.
um, I think carcraft proved this a number of years ago. it's displacement that matters, not bore or stroke.
they built up 2 equal displacement SBC LS1 motors, IIRC, both 383 displacement. one was a stroked 5.7 (which are, IIRC 3.9" bore), the other used a 5.7 crank (3.62" stroke) and all bore to achieve the same displacement. both were built to have identical compression ratios. I do not remember if they varied rod length to have the same rod ratio, as well. I don't remember if the all bore motor was a 5.7 block and sleeved, or an aftermarket block, or what, but IIRC the article was in the early '00's, before the "big bore" 6.0/6.2L's LSx's were widespread or even available.
they used the same heads, cam, intake, headers, etc, so the two engines were identical except for the bore/stroke ratio to come up with identical displacements. the results? the larger bore/smaller stroke motor made slightly (like 5hp and lb-ft) more HP than the all stroke motor, their assumption was it was due to less valve shrouding, but it was less than 2% difference, which basically means they made identical power.
so build up your two hypothetical 440 cube motors otherwise identically (cam, compression, induction, exhaust), they should make the same amount of power.
I really wish I could find the link to that article again...
Last edited by patrick; 12/16/0911:07 AM.
1976 Spinnaker White Plymouth Duster, /6 A833OD 1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!*** 2011 Toxic Orange Dodge Charger R/T 2017 Grand Cherokee Overland 2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
