This is from FORD:
After market Shifter Stops
All TREMEC transmissions are designed and manufactured with built-in shift stops to prevent over shifting. Therefore; shift stops on after market shifters are totally unnecessary when used on a TREMEC transmission. TREMEC "TR series" transmissions have multiple shift rails with shift stops on the gearing.
When installing an after market shifter on a TREMEC transmission it is best to remove the shift stops to avoid miss adjustment, and the potential of the screws vibrating lose. A misadjusted shift stop can cause an under-shift, which may lead to a gear jump-out situation. If the transmission jumps out of gear, the shift fork can be bent causing permanent damage to the transmission.
TREMEC shift forks are designed to take loads up to 1,000 lbs. However, a gear jump-out may well exceed 1,000 lbs. of force, which may result in a permanently damaged transmission.