Thanks for all the helpful posts! When I purchased the car 3 years ago, I was told it was a mid 70's 455 block. I am really happy to hear that I have a 400 since my car is an original 400 car. Not that it makes it correct or anything...just my call-out emblems will be accurate.
Kyle - eventually, I do plan on rebuilding this engine. It'll probably be next winter's project. It runs really good now and is still in the car, so I wanted to assemble the car, try to enjoy it during the summer and then see about breaking her down after that. I'll probably be extremely active on here when I do rebuild the engine since the folks on this site have a lot of knowledge and are willing to assist with advice. Quite honestly, I'm a bit curious myself. Maybe someone else has torn down a 9799914? I'll definitely keep you informed when I find out.