i would just pull the snout/rotor combo out and shove it in to the case turned 180* this wouldnt effect the twist of the rotors and only change the direction the pulley needs to spin to compress air through the outlet. as long as the bolts can go back in to secure the snout to the housing, then i would be all set.
in reguards to fabrication, its a case of dissasembling the snout and chopping it down. then i would machine out the nose to fit the bearing back into and chop down the snout shaft to the correct height. take off the snout fins and that part would be done.
after that, i would make two brackets that had bearings pressed into them and run a ss shaft through it with two pullies on it. voila`
