Lets use 4 rather plentiful motors- 318, 360, 383 and 440. Keeping it simple, all A-B body styles with average weight of 3500 lbs. Allowing for a 904/727 trans(comes with the car), 8 3/4/Dana 60( comes with), lets get some suggestions for complete motor and converter combo. Keep the rear gear at 4.10 or smaller(numerically). Tracks have or are flirting with 12.50 and 11.50 index racing, so let pick an index and see what combos are doable. Combo should be able to live for 3 years and N/A. Let's keep the total budget under 7K.