[iicarJohn]

... why it might be appropriate to talk about the 12C Grand Prix cars in relation to the 412 cars, I have the following observations:

Several years ago I saw the engine N. 412151 and observed the following numbers stamped into it. From what I saw, I am quite sure all the numbers are historic and not some recent manipulation. The numbers imply the following possibilities, if not probabilities, to me ...

The number 50101, largely filled with paint, is stamped on the right engine bearer, not far from the 412 ID plate. I think it is likely the crankcase that was used by the first 12C-36 (Tipo C) engine. It is also remotely possible that it was a crankcase that replaced the first 12C-36 crankcase at some point but I believe it carries at least the first 12C-36 engine number that was issued in 1936. Presuming the crankcase to be the original one bearing the number and not a factory replacement from later in 1936 or 1937, it probably first appeared on the scene in April of 1936 fitted to a Type C chassis that was perhaps new or perhaps modified from an existing small run of Tipo C (8-cylinder) cars. One or two similar 12C cars were tested in April at Monza and one was crashed by Farina. Shortly after, three 12C-engined Tipo C cars appeared at Tripoli in May of 1936 and this crankcase was quite likely in one of them. The three cars were driven by Tadini, Nuvolari and Brivio. Only once more would three 12C cars appear simultaneously in 1936 and this was at the Vanderbilt Cup (New York) late in 1936. Otherwise, 12C appearances were made in pairs or by a single car on its own. For 1937, three 12C cars also appeared simultaneously on a couple of occasions. So, we know that there were at least three 12C-36 engines based on public appearances alone. There is a boat 12C engine from this series as well.

The highest 12C engine number known in this series at this point is engine N. 50104 but it is certainly possible that there might have been another engine or two in the series. Engine 50102 is not known today. Engines 50103 and 50104 are both with Alfa Romeo. Engine 50103, bearing additional numbers of interest to this discussion, to be discussed later, is installed in the Tipo C N. 50012 that is normally on display in the Alfa Romeo Museum, the original 8C (3800cc) engine for that car having remained in the USA until recently at least. Engine "50104 M" is on static display in the Alfa Romeo Museum with a sign that indicates that it was used in a boat ("M" = "Marino") but there is nothing to say that it might not have had earlier use in a car? Of course, if someone can tell us that 50104M was fitted in a boat from April, 1936 until sometime in 1938 (at least) then we might get the impression that it was probably not used in a car. So, our study should include at least one boat as well!

It might be pertinent to point out that the engine configurations/specifications/designations could change quite dramatically without actually needing to cast another run of crankcases. Crankshafts and cylinder blocks could have formed the major portion of the changes that came about to make up the subsequent "12C-37", "312" and "412" configurations. It does not take much of a dimensional change in either stroke or bore to change the displacement of a 12-cylinder. The multiplier is "12". Not just "4", "6" or "8". For proof you need only look at the "Colombo" Ferrari V-12 that went from 1500cc to over 3000 in a package that was nominally the same exterior dimension. And, as you'll see, the numbers seen to date tend to imply that the Alfa Romeo 12C crankcases were used several times.

The crankcase of engine 412151 (ex 50101) also bears the Alfa Corse number "71", something of a disjointed (semingly a "new start") continuation of the Scuderia Ferrari numbers that had come before. The implications of this are not absolutely certain, but since the first Alfa Corse GP project after Ferrari left appears to have been the 312 car of 1938, one has to wonder if this crankcase might not have become the first "312" crankcase at that time? It is also possible, if unlikely, that Alfa Corse built another (late) "12C-37" or some other interim project after Ferrari left Alfa Romeo? As a matter of interest, it is probably germane to point out that the three "308" cars known today bear Alfa Corse numbers "77", "78" and "79". Numbers "77" and "79" still exist as "308" and the number "78" car was a "308" special (3800cc engine) that went to Argentina in 1939. So it seems likely that the 12c and 16c cars might have been numbered by Alfa Corse mostly earlier than most 308 ... or the 308 intermingled with the "312" and "316" cars.

For those who would like to have a look at an overview, there is a document that I attached to a posting in another thread discussing Scuderia Ferrari (and Alfa Corse) numbers.

Then, of course, there is the "412151" number stamped in the crankcase (as well as the ID plate) of the crankcase that was "50101". That is quite an interesting history for a crankcase! All recorded by the numbers. And, I suspect some numbers have been removed ... or I simply did not see them, having removed no paint nor having done any cleaning. The crankcase went from GP car to GP car (of another formula) and then to "sport" car. Perhaps there were additional uses as well but we may not get to know. Of course, the crankshaft and monoblocks might have changed one or two times (or more) along the way, but someone who is racing on a budget might have been very happy to recycle anything at all.

Turning to the aforementioned 12C engine N. 50103 that was fitted by Luigi Fusi many years ago to the Tipo C (8C) N. 50012 at Alfa Romeo, the following numbers have been observed by myself:
There is an Alfa Corse number "78" which was most likely assigned originally to a 312, 316 or 308. Indeed, as mentioned above, the number "78" exists on a "308" today that was fitted with a 3800cc Tipo C engine and sold to Argentina in 1939. The fact that this number appears on the 12C crankcase "50103" might seem to imply an Alfa Corse numbering of a Tipo C (12C-36) which seems extremely unlikely. However, the same crankcase also bears the number "51205"! This would seem to indicate that it was "12C-37" at some point as well. Assigning the number "78" to a 12C-37 seems only a bit less unlikely than having assigned it to a Tipo C (12C-36) engine. It seems to me that this would make it most likely that the Alfa Corse number "78" was assigned to the same crankcase when it became "312". Of course, this means that there are implications as to the earlier use of the chassis used to build the above mentioned 308-3800 special that went to Argentina! As with "50101" (aka "412151") the number stampings themselves all take different styles from one another but are consistent with those seen on other Tipo C and 12C parts (chassis and engines) and I believe all the numbers reported here to be genuinely historic.

To be continued ...