Combines 4420 vs late model 4400

Basically everything you just mensioned will interchange. Most 4420's had a 359 cu in engine but the 429 that the 4400 has can be bolted directly in its place. The last year of 4400 even had the flat style rotary screen just like the 4420.

Thanks for the info, JHEnt! I managed to do a little more research and, aside from the engine and rotary screen, it seems the concave is the only thing that differs, and my local dealer tells me that even the 13 and 14 bar concaves will interchange.