[Kurt in NJ]

The idea was that the dealer could remove the sleeves and replace them in the chassis ---if just one cyl had damage just that one could be replaced, it was common to bore cyls in the chassis, that got a lot of metal in the bearings---sleeves solved that, they came pre finished, already honed, made it easy for the rebuild program, and better metal could be used for the sleeves---actually the sleeves were case hardened steel

they were also used in the rebuilding program, once the block got to or wouldn't clean up at .060 they could fit it for tin sleeves