Any ex-Force O/B guys here?

i believe that model tach is fo a force only. i had a 86 bayliner with a force 125 and when i tried to replace tach i found out i could only use that big ugly square one. it was easier to replace the motor. when i pulled the force off the boat it was running as well as a force could run. still i couldnt give it away. the mechanic that did the swap wouldnt keep it unless i gave him 20 bucks. so i hope youhave better with your force than i had with my runnin on 3 cylinders ,always leaving me stranded, overwieght, underpowered, gas guzzling p o s!