390 feet waterline, 414 feet 6 inches over all
415 feet waterline, 438 feet over all
You have compared the waterline length of the Knox to the overall length of the Ramsey. In fact, Knox is considerably bigger!
This project you are proposing is about like saying, "I plan to convert a Fletcher DD into a Gearing DD." So much major surgery needed that you would be better off paying the price for a resin kit of the actual class you seek. I have followed your posts here on the subject. I can see you probably don't like the resin price, and think you will get a plastic kit cheaply and convert. However, to do the conversion with any particular accuracy will require so much modification of the kit, that the cost will go up nicely.
Craig has recommended a nice 1/700 waterline version of the Knox class above. I have that kit, and found the build enjoyable, and the cost in 1/700 would probably be more to your liking. (Then there are the resin 1/350 kits you already know about from your past posts.)
Best of luck to you if you still wish to proceed with this project.