.xls format If the attachment to the list fails it is at: http://texasvolksbus.org/4cylDisplacement.xls Common numbers already filled in 2 free columns/rows for punching in numbers to play with Someone correct me if wrong but longer stroke gives more low end torque for equivalent bore and bigger bore gives more top end for equivalent stroke. Or is it the other way around? When I was still going to Jerome and BBB Ronnie F. from Havasu swore by the 1835 he built for his split. And I saw him haul a$$ up the hill in Jerome with that bus loaded so heavy it was squatting. @Steve Chamberlain --- you might want to call him and see about having one built or see if he's found another formula he likes better for heavy hauling --- http://www.bustoration.com G2