Regarding the origins of the engine this debate was made before in other threads I seem to recall but gtv2000 expressed the same feelings I had since I have both the book "Nel cuore dell' Alfa" by Busso which quite clearly states how Busso was unhappy that Chiti was given the engine when Busso's team had projected it. Indeed in the same book Busso explains how he researched the magnesium castings for the chassis from France subsequently made there and used on the race car. So much of the initial projection of the tipo 33 race car was in my opinion done in house headed by Busso/Satta. When Autodelta took ownership of the project surely Chiti could have developed and changed the engine according to best principles (learned from previous experience) but the skeletal framework of the engine was not his nor part of an earlier engine in my opinion.
One has to also consider when designing the new race engines there will in my humble opinion always be parts/sections that remind one of other previous engines, especially in this case other Italian engines so new engines could use a similar (but improved) evolutionary layout unless the design is completely revolutionary.