Great that you got the FTP working.... Does your 140 have a sleeve inside the valve to reduce the volume?.... If so, take it out.... You will make the gun easier to pump, with a lighter trigger pull, and the velocity will continue to build more past 5-6 pumps.... Typical numbers for the ones I did are.... 515 at 5 pumps, 610 at 8 pumps, and 660 at 10 pumps.... the strongest one topped 700 at 10 pumps, but had a bored valve.... Some other things you can try....

Drill out the flow-through bolt to 5/32" front and bottom....
Drill out the end of the valve (the part the quad seal slides over) to 5/32".... using numbered drills, ONE SIZE AT A TIME.... go slow so you don't expand the outer surface....
You have already fitted a poly-port, but make sure the barrel port is also drilled to 5/32" (again, one size at a time, making sure the drill doesn't grab and damage the opposite side of the rifling).... Carefully deburr the inside of the port to make sure it doesn't damage the pellet on loading....

The extra volume inside the valve by removing the sleeve reduces the pressure at a given number of pumps, which reduces the trigger pull.... The velocity is unaffected at about 5-6 pumps, tends to be better above that, but slightly slower at 2-4 pumps....

Bob