BPE offers (Or at least did) as high as a 4.250 stroke. The 4.125 stroke actually fits better with less clearancing the block than a 4.00 stroke because of the longer rod and smaller rod journals.
And I haven’t done any dyno testing but all the research seems to indicate the 4.00 and the 4.125 make the similar hp, but the longer stroke makes more 20-30 more TQ.
