Put the words Indigo Prop into the window you get when you click on the "search" icon, upper right part of this screen. There seem to be two happy owners with one.
Others may chime in here any minute, what with so many Ericson owners with the A-4 engine.
I went with a CDI urethane prop for my '74 E27 with Palmer P60 engine. It had a 10x6 but I switched to a 12x7. My backing performance was greatly improved. I lost a few rpm's but I can make 6.2kts with an easy cruise at 5kts. The boat's acceleration is also improved. The Palmer P60 is a 4 cylinder gasoline engine like the Atomic 4 and has 22hp instead of 30.
I just installed the CDI prop. I LOVE it my boat has more power and i even have to lower my idle because my idle speed it to high for my marinea. The CDI prop gave me better reverse and forward speed and control. PS I have an E27 as well but the Universal engine.
Tom, There is another threat going on regarding re-proping an E29 under Maintenance & Mechanical. Since you appear to have used the CDI for a season, I would be interested in how it functioned over the long haul. My E29 is on Lake Michigan so it's use in the lighter freshwater would be usefull.