The LX was redesigned once again in 1961 (main case enlarged-new bell to fit FE modified pattern-modulator valve). We know from a previous experience on the LCOC FORUM that the earlier 58/60 TWIN-TURBO main case to bell pattern is smaller in dimension than the 61/65 redesign.
So in order to transplant a 61/65 430, the unique LX has to go with it. Now the other question is can the extension housing/output shaft be adapted from an MX? LM MPC lits a differnt tail housing/output shaft for the later LX. There is also a unique extension housing to main case gasket. One would have to put both on the bench to discover interchangeability.
The special 462 C6 (66/68) and the 460 LINC CONT specfic C6 (68/69) had this same type of driveline. But to me (IMO), the C6 could be more easily modified to fit a normal chassis as there were so many design variations over the years to draw parts from.
Just something else to think about.
I think this subject needs to be narrowed into categories;
58/60 MEL Specific (and all variations within)
61/65 LINC 430 Specific (and all variations within)
66/68 LINC 462 Specific (and all variations within)
68/69 460 CONT Specific
The singular term MEL cannot emcompass all of the changes over the production years. The MEL DIVISION was terminated in late 1959 and further design was LINC DIV specific.