Well, part number is the same for the V10 and the MAGNUM engines. The LA's didn't use an oiling hole in the cup for pushrod oiling so that part number is different. Not sure if they'll still work regardless.
As for the big blocks, how are you going to prevent them from rotating in the bore? Or any non-roller block LA. I know how the factory did it and you might be able to add that to an LA block with some creative fab work, but not sure the OEM spider will work on a big block.
But then you have to deal with the stock roller lifter oiling hole being higher on the roller lifter body and getting uncovered at full lift. So you either sleeve the bores or go with an aftermarket roller lifter designed for this swap. Unless you are using a roller LA block, which have taller lifter bores.
