Freeze plug?????

[OUbesto]

My c10 has been leaking a fair amount of coolant but not while it is running or within a reasonable amount of time after engine is turned off. However, its not until the next morning that about a 1/2 cup of coolant is laying on the garage floor. So I jacked up the front end and the only place I could see a possible coolant leak was coming from the freeze plug(?) located (circled in red in pic) just above the starter on the passenger side of the engine block. I recently purchased truck so I don't have any history but it appears to be a fairly new plug. I hooked up a socket and tightened it a number of cranks and it seemed to stop leaking from its perimeter. I wasn't sure how tight to crank it. I had to leave the truck last night which is about 50 miles where I store it so I'm not sure if leak has stopped. Any thoughts if I'm on the right track here? Any suggestions? Is this plug the correct solution, or, is there a better or more effective option to consider?