That's quite right - the Crusair is not covered in the TC that applies to 'Masters and early Vikings. Also, not only will W&B be an issue, but cowl width will be as well. You cannot fit an O-470 into the cowl of a 14 series aircraft of genuine Bellanca manufacture.
First, as Mark notes, look at the prop and when it was last overhauled. The clamps were subject to an AD in '85 with a grace period until '87, which was changed to a 100 hour inspection of the clamps, until '97 when they had to be gone, gone, gone. If the prop has not been overhauled since the mid '80s the minimum cost to bring it up to date would be in the eight to nine thousand dollar range.
Next, look at the engine and when it was last overhauled. Many parts were upgraded with better ones until Lycoming plugged their ears with their fingers and began shouting "Yah, yah, yah....I can't hear you," whenever you said O-435. Many of these engines were rebuilt with updated parts, half inch exhaust valves, and high compression cylinders, giving them 225hp...theoretically. Look at the logs, see what's been replaced and when it was replaced.
Let's stop here for a moment. If the prop and engine have not been overhauled since the 70s or early 80s, and haven't been run since the Reagan administration, don't waste any money on them. Proceed to the Franklin option.
Franklin stopped making new engines, but engines are available. Your first thought might be to grab one of those 220hp models. However, the one person I know who has that installation - Mike Grimes - said that if he were not an A&P/IA with close ties to the feds, he could not have pulled it off. This would give you the option of a constant speed prop.
Others will have to counsel you on the other Franklins and the prop options, given that the Aeromatic is hard to find in serviceable condition, and many owners have gone with fixed pitch replacements, alas.
Get back to the group with what you find
Jonathan