With that new GTQ wheel I think you are going to be seeing much more air flow lower in the rpm range. That means giving it more fuel down low.
Going from 72s to 83s will be a help of sorts but you will be tuning for a newer, bigger turbo so its a wash either way.
One thing I have noticed going to a 400 trans is that all of a sudden you have a motor that revs between 5000 to 6000 going down the track. That is the effective rpm range you will see on datalogs.
The 400 is really meant for higher revving motors, meaning 7500 to 8000 and up. Its not that it wont work, it does. And every guy who goes to the 400 does it because they last longer against the 800 ft lbs of torque than a 200 will.
Dad is running a Stage 2 block, 74 twin bb, and 83s with a FAST unit now. He is using a 400 also. This 74 spins up so quick it is not even funny
For the stage motors that are revving to 6000 to 6500 I honestly think that the 200 is the best way to go. It is not until you start revving the motor above 6500 that a 400 helps.
He will be switching cams here soon. He will be revving the motor to 7500 and I think that will help him out a lot using the 400 trans.
Let me know how that GTQ wheels works.
