Picking gears

Like anything else, it's a game of diminishing returns as you get closer to "right", but as AJ said - once the gearing is "right", other weaknesses will rpesent themselves. If you own a race car the assumption is a peakier power curve and move race oriented suspension and tires, then yes, gear to be a few hunrred rpm above your peak HP. Once you say "it's a street car, and I race it" that kind of goes to pot because the "right" gear will not be very streetable unless you live in Manhattan and never drive on the highways.

I put "right" in quotations because it's very subjective.

My advice would be chose a gear that keeps your highway crusiing rpm just above the convertor's stall speed. So a convertor of 2800 rpm, I'd be looking at 3.91s or 4.10s. Your best ET will be totally dependant on your ability to tune the engine and suspension, and how much money you put into the suspension and tires. With a set of slicks, 4.10s, and a decent 360 I would expect you to be in the 12s, with potential for high 11s at sea level with a good track, assuming you suspension is optimized.