727 Time to rebuild
I look at it this way on grinding the throttle valve, if you grind it all the way to what Trans-go says and it's too short you may not have passing gear at moderate or higher speeds. If you only grind half of their recommendation off and it hangs in gear too long you can always back off the throttle pressure rod (or cable) adjustment until you get it where you like it. That's sure a lot easier than taking the valve body back out and finding a throttle valve to redo it with. JMHO