The fact you can hold those 2 spark plug wires means you do not have spark on those 2. . Is there water intrusion? those motors are known for exhaust gasket leaks. Timer base connected and moving ? Get an open air spark checker. make sure spark jumps 7/16 "
75 has different block and head. Same bore and stroke between the 2.
I would build the 60 as its a better all around motor. are you sure that 75 has trim and not just a tilt?
