Triggerfish, the messed up calibrations were in the OE (68-71) AVS's only. the later AVS thunders would not have that issue. now you can get the OE AVS's to run like a scalded dog if you put some work into em but for the nth degree of performance there are much better carb choices. but on the early AVS's, He may already have em/they may be required for class rules/he might not want to buy new carbs.