'76 Caprice won't start

I just got my dad's 76 caprice. It has about 47,000 miles with a 400 engine. It was starting while sitting but I was going to run it and now it won't start. Tried new battery, plugs, filters, new gas tank. Got any ideas?

I am closing this thread because it was duplicated in the Classic Chevrolet sub forum, where it has received a response:
http://www.automotiveforums.com/vbulletin/showthread.php?p=4792488#post4792488