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Right off hand it looks like you have a 283 V8 with a 2.5:1 reduction gear.
The CC motor tag (with Chris Craft logo and their own Chris Craft serial number) will normally have the type of transmission called out in sort of a code. That 25 you are seeing most likely indicates the 2.5 gear reduction, which if left in the boat, would make you want to use a much larger size prop, both in diameter and pitch, than a direct drive.
A 20' barrelback would take a direct drive normally, and your transmissions may well be able to be adapted to this. Some paragons can, others can't. With direct drive I would think you would be spinning a 13x14 prop, or something close to that, perhaps a 12x15, but my first starting point would be a 13x13 just to see how it worked on the rpm band. I doubt if you will be able to spin the bigger props with the stock 185-hp.