THEORETICALLY greater airflow.
In point of fact the larger TB actually flows more air than the engine can actually take in which is why 2.9's have little distinction in throttle position above 3/4throttle.
This however can be used to advantage.
Not to get more air into the engine, but to use the larger TB with the 1988-up TP sensor on an 88-up 2.9 engine...
Runnig the SAME ammount of air into a 1988-92 2.9 while the computer THINKS the engine is getting
whatever ammount of air the smaller TB would deliver at 3/4-7/8, this keeps the management system
in "closed loop" and running relatively more lean.
To understand the point of this you need to know that the 2.9's by design and setup run TOO rich under most circumstances (look at the layer of BLACK SOOT inside your tailpipe)
and they can run much more lean...
This is how you get more power AND 25+ mpg from a 2.9.
The real secret is to NEVER give the computer a Full throttle signal from the TPS.
With the BIG TB on a later computer/engine this is EASY.
AD