Not all 383's are external balance that use the 400 Balancer & 400/454 flywheel/flexplate. Make sure you get a harmonic balancer and flywheel that are the type for a 400.
even with rods "cleared for strokers" you still have to make sure it clears the cam. Small base circle cams help alot. The last two 383's I built I had to clearance my profiled stroker rods with a standard base circle cam.If you use rods "clearanced for strokers", do you have to use a small base cam? The only one I've ever built we used stock 5.7 rods and ground the rod bolt.