5411 replacement
The Universal 5411 was a Medalist block built between 1977 and 1982 and was rated 11 HP at 3000 RPM. It replaced the 30 HP Atomic four in the Catalina 30 evolution. As you state, it is underpowered for the application, even when running like new. Catalina later replaced it with the 21HP M-25, another Medalist block, and then the 23 HP M-25XP, based on a Kubota block. The 25'S were a little overkill but the choices were somewhat limited. The best choice for repowering a Catalina 30 is the Universal M3-20B, a current production engine rated 20HP at 3600 RPM, again on a Kubota block. Minor modifications are required, including getting top clearance, but the installation is quite straight forward, dn drop-in. We generally have an M3-20 in the show room because it is a popular engine. The engine, with a reversing gear, currently has a list price of $7,080.00. We would be happy to discuss this with you further if you are so inclined. I believe that the extra HP will preclude the use of your present reduction gear, but we do consider trades.