well ur 4.7 revs higher and makes power at higher rpms so a larger throttle body would only help not hurt. You will sacrifice some low end but it won't matter much with the 4.7 since you're revving the motor higher. The 5.9 on the other hand is more inclined for low end torque. So if u give up all the torque the motor still can't rev high enough to make high rpm power, so staying with a significantly smaller tb opening works the best. I'm sure if the 5.9 was a dohc motor that could rev to 7k or so (wow how sweet would that be?!!? :drool: ) then a large tb would do the trick nicely. For instance looking at some honda tb assemblies, i think upwards of 70 mm, maybe even 80 mm if i'm not mistaken are common, but then they can rev high into the 7k rpm range and cars like the integra type r and s2000 go into 8k-9k range.
