I bought a new one from Dorman a few years back for a 318. It was around $60
It may be available from Summit in the replacement parts department.
I believe that is where I got mine from. My 2 cents..
Be careful screwing around with pans. Especially some of the knock off replacements, (I think Milodon?) interfere with some performance oil pumps Make sure you check that. It is possible for the rear of the pan to stress the pump and crack the casting.
I removed an oil pan of one 318 engine I have. This one is stamped 294. The gasket kit I initially got for the spare pan fit on it perfectly.
The shape looks like the damaged pan stamp 288 but hard to tell if it's the same depth. I clean it out and sand it to bare metal for inspection. Prime it and paint it Chrysler blue. The plug is going in and out easily and got a new seal for it.