Yes, you need to tap the top row of head stud bosses, probably a 5/8x18 plug, and then redrill and tap the top row for the wedge pattern. They will overlap slightly at the top but will drill into virgin block material within 1/2" because of the taper on the hemi stud boss. There will be some mis-match on water passages if using stock 440 heads, which can be brazed up. Oil drainback on the hemi block will also need to be blocked.. Most aftermarket heads are profiled the same as hemi block and should cover the oil drainback. I think you would need an external drain line from head to block on a B-1 head but not positive. Can't think of any other issues, but definitely can be done with a good machinest.