Rebuilt top end of engine now carb idles much higher?Please help

Yes it’s a big block a 383. I tried reusing the old valley pan when I reassembled it again and again. I’ll order a new valley pan(what brand) and maybe I should use a special type of intake gasket possibly between the intake and valley pan? Should I also use the copper spray and spray all meeting surfaces with the copper spray and lay down some oil and gas resistant permatex?