R3 block info

I recently pick up a r3 block part number p4876671 which is a 9.20 deck,48 degree,four bolt 340 main siamese.This is new a still in the pallet from mopar.I don't know a lot about these so looking for any information would be great.Are 48 degree w9 heads still available or are there something else out there?What is the max stroke crank this block can take with the short deck?
Thanks