[decooney]

Its an answer that depends on other inputs too. It sort of depends on what spec motor/cam you use, what trans you'll use, how tall your rear tires will be, and what type of driving you will be doing.

e.g. If you build a mild FE, than you might not even be happy with 3.31s for freeway driving, and 3.54s or lower will be worse. Bigger cams in the FEs do great with 3.31s on the freeway, however if you do a lot of freeway driving, then a 5-speed is going to be a must if you choose spin the motor less. The more I've tried different combinations, the more I've learned how each change can make a noticeable difference.

Do you have an idea of what cam spec, trans type, tire size, and driving distances you'll be looking at for your ERA?