Dave, the difference between a 216 and 235 may be small enough to not see much change in the air/fuel ratio, particularly with a spark plug check, but it does happen. If you go from a 350 to a 454 with the same carb, you will change a bunch of jet sizes. I had experience in working with carbs developing fish hooks (fuel curves) and emissions settings, and worked along side some of the best Holley reps. Also worked with Bendix/Autolite in spark plugs and O2 sensors. Have put in a lot of dyno time while doing engine and component development.
