My new project

So next I decided to investigate why it wont at least crank over. I checked power to the starter and was good. I checked ground and then tried to crank it with the battery jumped off of my truck and it just clicked like the solenoid was engaging but the starter didnt spin at all. I was pretty much out of time so I just pulled the starter out and went off to work. I will test the starter soon as I get some free time then once I get it to spin (or replace it) I'll go back to trouble shooting the motor some more once its able to crank over.
Should I cut off the muffler before I try to crank it over? What do you think?