Guest Anonymous Posted December 15, 2001 Share Posted December 15, 2001 For a while topics on increasing rod to stroke ratios in SBC have come up. Has anyone done something similar in BB? Forgive the unimformed... Thanks! Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 18, 2001 Share Posted December 18, 2001 btt Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted December 18, 2001 Share Posted December 18, 2001 sure . the common bbc has a 6.135" rod, the common aftermarket rod lengths are 6.385", 6.535" ,6.635" 6.70" and 6.80" look here, http://www.callies.com/catalog.htm http://www.oliver-rods.com/ http://www.crower.com/CGI/master.cgi PG 155 http://www.flatlanderracing.com/index.html go to connecting rods now just some info.a 4" stroke 454 would have a 1.53 rod with the stock rods and custom pistons and 6.535" rod gets you a 1.63 ratio.the Ideal ratio for efficient torque production is about 2 to 1 but most production automotive blocks don,t have enough deck height to allow that, the best easily obtained ratio would be with a 3.76" stroke crank from a 427 with a 6.535" rod and custom pistons giveing you a 1.73 to 1 ratio (but that would make the area for the oil rings overlap the piston pin and require additional support rings) . or if your useing a tall deck 10.2" truck block instead of the 9.8" automotive block you can get to a 1.8 ratio with a 6.8" rod and a 3.76" stroke! btw just as a referance the 327 sbc that some of you think revs so well has a 1.75 ratio and the 302 Z28 engine that everyone knows can be made to scream has a 1.9 to 1 ratio, and most true racing engines like the formula-1 and indy car engines run 2 to 1 or higher ratios Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 21, 2001 Share Posted December 21, 2001 Thanks for the info. Anyone else have opinions or experience? Quote Link to comment Share on other sites More sharing options...
Guest Will Posted December 29, 2001 Share Posted December 29, 2001 It would cost an arm and a leg, but here goes: Aftermarket aluminum big block with 11.625 inch deck height bored to 4.440, teamed with a custom 3.470 stroke crank and custom rods in the neighborhood of 8.625 inches gives a R/S ratio of 2.48! This configuration (4.440 bore x 3.470 stroke) is the famed CanAm 430 used by team McLaren in the first half of the Can-Am series in the late 60's. They used a 10.2 inch deck height, though (I think). With custom pistons quench matched to Tim Fueling 3 valve heads you could run 14:1 compression on pump gas and get 25 mpg with 500 HP on tap, OR go with 32V heads from www.araoengineering.com and you could run 13:1 compression on pump gas and have 1,000 HP. Quote Link to comment Share on other sites More sharing options...
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