ARGTAReg : If you have photos of the 1964 ATS 1,5L V8 engine from an overhaul or technical drawing, it would be interesting to compare with the insides of the Tipo 33 engine. We know little about the ATS engine, but something about the Tipo 33 engine here. So more info on the ATS engine is what we need!
I have numerous photos of ATS T100, but none of them is particulary good for confronting. However, here they are and (much better for the purpose) Ferrari 156 (mainly Chiti’s project) and Ferrari 158 (started by Chiti and then finished by Forghieri) that is 1,5 liter V8. As you can see, 156 engine is V120°, nothing like V90° of T33, while 158 engine is V90°, 8cyl. and almost identical architecture as T33. Whats more important is interior design. ATS, Ferrari 158 and T33 are all 90°, with similar bore-stroke geometry, have all twin OHC driven by chain, same direct valve opening, 45° inclined valves, flat crank with 5 main bearings for the counterweighted shaft, dry sump … and so on in many similarities. It is clear that those engines are close relatives, beside the fact that Chiti was among the most brilliant racing engine designer ever, and those motors (except ATS) confirms that.