i did that mod to my brothers 92 s-10 4.3L roch tbi unit and it didnt seem to change anything, one skinny narrow part of the gasket split on me it was stuck bad, you have to be damn careful you should soak it with something to help keep from tearing the gasket it can be very tricky. soem carb cleaner would probably help unstick it im sure, dunno,.
or just get a regulator and a TPI pump for a third gen F body or impala or something and turn the volume down with a regulator
TPI pumps put out twice what a TBI pump does, so..
if you are wanting to increase this cuz your spray is weak then maybe you just have a tired pump, get a new one