I was hoping it would be easy, too. It turns out that the only approved 150HP engines for the older 8KCAB's are IO-320-XXX and AEIO-320-XXX. The IO-320 must be modified by adding the baffle plate/flop tube inverted oil system to meet the type certificate. The AEIO-320 includes the Christen system and is shipped from Lycoming with the Christen parts in the crate. I have the IO-320 engine and the baffle plate/flop tube was removed during overhaul years ago. It appears the only legal way to use the Christen system is to convert the IO-320 to an AEIO-320. The conversion is not that hard, but requires a new sump($$$) and accessory housing ($$) along with the Christen kit($). I ran across an old 337 from 1975 that made this conversion and referenced STC #SA2854WE and a "Michael Dewey Report MDA1-R22074". I hope the STC and report information will describe an easier or cheaper way to make the conversion. So far, I can't find any information on either and was hoping someone here could help. Thanks for your reply. Dean