So would I be correct to say if I have different numbers on my cams such as 551 and 1213 they are different. Only my surprise is that I was sold 2.0 ltr Alfa TS cams and only noticed now that my original 1995 B cams have the same part numbers on them .
I was under the impression the 2.0 ltr Alfa cams gave a little more power . Could it be the case that the first production Barchetta had these higher lift cams fitted hence the more power they were said to have 138bhp .
Anyhow Im having some more tuning and work to my cylinder head and the valves recut and refitted the 2.0 ltr cams .
If you spend a little time with ePER you can (starting on the Barchetta link I gave) click a cam part number and it will expand the info on another page. There you will find "More Details" which shows which cars it was/is used in and also a "Replaced - Replacing" P/Ns and date. You can follow the previous/replaced P/N and then do "More Details" again
I can see that the "B" cams were also used in a Lancia 2.0, Coupe 2.0 as well as Alfa 1750 plus many other Fiat cars so it appears they are quite common parts for different engine sizes.
I can't be exact or specific because I'm time constrained at the moment. What you could do is tackle the hunt in reverse. Use eEPR to looks at the cams in a chosen Alfa 2.0 car/engine and see where with more details that takes you to.