I didn't take pics 'cause my camera is a POS but here's the sccop on my 440Source crank

1) 4.375 stroker
2) no scallop on the back flange - probably not necessary for drilling with the longer throws.
3) flange is nicely finished with consistent thickness
4) front and rear throws are drilled right through with 5/8" bit. Drilled straight.
5) middle two throws are partially drilled - about 1-1/2" deep, 5/8" bit, AT AN ANGLE. Had they drilled right through then these two holes would have come out in the thrust area as well.


Why are they at an angle? My guess is the bit isn't long enough to come in from either end without the chuck hitting the crank somewhere. That may have something to do with the torsional load on the bit over that length. Most factory cranks I've seen have much larger holes so the longer bit would tolerate the torsional loads. Or maybe the manufacturer is just too cheap to buy a longer bit.