H22 pistons = 87mm. I don't know of any way to get a B-series block out to 87mm and if such a method does exist, it would be so expensive as to make using OEM pistons borderline sacrilege.

Another more basic problem. B-series motors have iron sleeves. H-series motors have aluminum/carbon composite sleeves. In a B-series motor you can use aluminum pistons just fine. You cannot use aluminum pistons with the H-series sleeves because of the metallurgy so the stock H-series pistons are coated as to not seize up on the cylinder walls. Slap em in the iron cylinders of a B-series and you're guaranteed problems.