I've been told by several very good heads up racers that a motor with a large bore and short stroke (less than 4.250) will make more power and accelerate faster than the same size C.I. motor with a smaller bore and a longer stroke
My next all out motor will have a set of B1-MC heads on a Koleno high nickel 4.500 bore size block to start with and a 4.375 stroke fully counter weighted old Sonny Bryant top fuel crank due to the price and availability of them in SO CA back when I started this project That crank was originally a 4.250 stroke crank with standard Mopar rod journals sizes that I had offset ground down to BB Chevy 2.200 size and offset ground to 4.375 stroke. I'm going to use a set of forged steel 7.100 long Molnar H beam steel rods with 2.200 big ends and .990 small ends
I would love to make a similar motor with 4.500 or bigger bore size with a 4.0 stroke crankshaft with the Honda rod journal sizes(1.880?) with a long rod
Do you really want to make a motor that will need to be revved between 6000 to 9000 RPM to make power
I normally don't but this next B1-MC motor will probably be one like that
High RPM, high dollar and high maintenance
I dyno tested a 526 C.I. 440 bracket motor (4.380 bore with a 4.375 stroke crankshaft) that had a set of both Indy SR and 440-1 heads on it , both sets where M.W. intake sizes and both had 2.250 intake sizes, I used the same cam, intake, carb and compression ratio for both tests.
The SR heads flowed 350 CFM at .700 lift and the CNC ported 440-1 heads flowed 370 CFM at .700 on the same flow bench by the same operator, the SR made 775 HP at around 7000 RPM and the better 440-1 heads made right at 845 HP at a little higher RPM(maybe 7200 to 7400 RPM. I sold that motor and gave all the dyno sheets and flow numbers to the new owner or I could give you more accurate info, sorry