Any reason a transbrake valve body would be slower than non tbrake VB

Trying to account for as many variables in the new combo as i can.
When i had the stock stroke 360, car ran a best of 11.26. 727 trans, 4500 8 inch vert
After a time, i swapped out the 727 for a 904 with transbrake, and new 8 inch vert. About 5k flash
The car immediately picked up almost a tenth in 60 foot, but further down the track i went, it gave that gain back. To the point to where the best it ever ran after the swap was 11.33.
Obviously i never saw the 1.5 tenth gain i was hoping to see.
Either i missed on the vert( better 60, but too loose on the big end) or something about a brake valve body( i have always footed it, have yet to use the brake) draws power...
Gonna be curious to see if the stroker with lots more torque likes this vert.
Tell us about the converter. Kim