Last night, I did exactly what you want to do, by accident. I had two motors, one with the cyclone starter, one with the old school Pull start. By accident, I mixed up the two outside covers which I had just had powder coated. Both engines look identicle from the outside, they both have electronic ignition. And they were both freshly painted.
Though it to took some moving around both covers fit on either motor. Which is what you were trying to accomplish, Putting an old cover on a newer motor. But then the problem started. The pull start. The old style pull starter does not work on the new motor. You can pull it but it won’t return, recoil. That’s because probably the cup on the flywheel is different between the two pull starters.
I monkeyed around with it for about an hour and just gave up. And finally figured out which was the old motor and which was the new one, and put the proper covers on the appropriate motor.
Bottom line, you’re going to have to do some work to make this happen. And it’s going to have everything to do with the flywheel. Because I could not position the cover to get the pull starter to work