55 mm cam

Do lifter bores need bushed on world iron block when going to 55 cam bearings

cam bearing size has little to do with bushing lifter bores.
they are bushed to correct misalignment as when cast

I would say it's done on 99.9% of any serious build. To neglect that invites potential cam and lifter failure.

I agree with Fred on this. Of the world blocks i've worked with, they all could've benefitted from correcting the lifter bore geometry. One of the ones i worked with the bores were already too large at .908 I bushed those and noticed the bore angles on one bank were off by a couple of degrees. Stuff like that reall messes with the camshaft timing events. the next one after that they were all too small at .903 so the customer just had us hone them to size due to budget restraints. Obviously the size of the bores is only one issue, but overall the quality control seems hit or miss on those blocks in most of the critical area's. Check the rear seal area and the main bore size and alignment. we've found some strange things with some those blocks. Others seemed to be okay in those area's. Bottom line, don't take anything for granted.