If the engine is in good shape to begin with then as long as it gets enough fuel and you pull 4 degrees of timing out, it will be fine. The spark plugs will need to be gapped a little closer (0.025"). 100 HP squirt on a 383 is OK. You may drop a full second in the 1/4. The car will actually be more driveable for the street compared with putting in a big cam.