A 700-R4 is a decent overdrive tranny, but I would research it to make sure it can hold up to the power of the 454.

Me personally, I would save up and put a Gear-vendors overdrive unit on it. It could handle the power, plus you would go from a 3-speed to a 6-speed.

The only down side is it costs about 2 grand

Just my 2 pennies.