Advice Needed

[Ole Blue 68]

Ok here's the problem. I bought my '68 a few months back from what I thought was a reputable seller who claimed it had a rebuilt 283 in it. At the time, the engine was spotless and seemed to run fine.

Now here I am less than a 1,000 miles later and the thing is springing leaks on me. So far, leaks have sprung up in the valve covers (fixed), oil pan and/or rear main seal and just the other day I noticed a small leak from where the cylinder head meets the block. So here's my questions.

1) Is it possible that this guy didn't bone me and something is causing these leaks?

2) How hard would it be to fix these leaks? I do my brakes and oil changes but have never tackled anything this big. Would I be getting in over my head?