[Woodz428]

A big reason for the smaller bores, even in the new car engines, is for a quicker and more efficient burn. There is only so much time for a flame front to move across a bore and the larger it is the less gets fully burned. In emmissions as well as HP, unburned hydrocarbons are wasted ones. I think it was last year that The big block build, I think by Kaase, used a reject FRRP 460 block and had the cylinders sleeved down just to help promote a more complete combustion. Since they are restricted to engine size, the current technology leans toward the smallest bore/longest stroke that is practical.