How to determine if the Nashmor module will fit in your 1.6 GPF Toilet tank
Carefully remove the tank lid, gently place it aside.
Look at the inside back wall for the size 1.6 GPF stamped into the ceramic.
Is there a minimum 3" wide space available on the right side of the center drain flap?
Is the front to back measurement 6.5" or 7" as shown in the photo?
If the last 2 answers were YES, the Nashmor module can fit your tank