I bought my car last year, and due to house remodeling I just got to tear into it. I have found alot of good to include the engine is #'s matching. I started digging deaper to find that it has a intake manifold # 9799068 and a carb #7028273 from what I can tell from the web this is a 400 RA II carb, and possibly a 1970 400 intake. Am I right? How rare is this carb?