There is an excellent book called "Mr. Piper and his Cubs". It is an excellent book which presents the entire history of the Cub. It continues up to the Aztec and Navajo. A great read...
On the topic of re-engining, a friend of mine commissioned the rebuilding and re-engining of a "Northstar" which is a PA-18 look-a-like. He asked me to take the project on, including installing a carburetted Continental 520 (at just short of 300 HP). I declined, citing the airframe builder's advice that 235 HP was the maximum for that airframe. He had someone else build it for him as a floatplane, and flies it occasionally.
I retain the fondness for the "powerful" 90 HP J-3 I used to fly, it did just fine.....