[he219research]

I am trying to sort out the “big-block” family of DB603 engines, focusing mainly on the three main production variants: DB603A, DB603AA, and DB603E.

Data from the official “Leistungsblatt” of the DB603A (Baureihe 0, 1, and 2) give us the following:
1750 hp at 2700 rpm at S/L
1620 hp at 2700 rpm at 5.700 m
950 hp at 2700 rpm at 10.000 m

1580 hp at 2500 rpm at S/L
1510 hp at 2500 rpm at 5.700 m

For the DB603AA, the corresponding figures (not from primary sources) are the following:
1670 hp at 2700 rpm at S/L
1450 hp at 2700 rpm at 7.300 m
1020 hp at 2700 rpm at 10.000 m

1580 hp at 2500 rpm at S/L
1370 hp at 2500 rpm at 7.200 m

And the DB603E “Leistungsblatt” give the following:
1800 hp at 2700 rpm at S/L
1480 hp at 2700 rpm at 7.400 m
1060 hp at 2700 rpm at 10.000 m

1500 hp at 2500 rpm at S/L
1380 hp at 2500 rpm at 7.400 m

All the above figures are without any extra boosting (i.e. no MW-50 / GM-1).

Most sources describe the DB603AA as being similar to the DB603A, but featuring the enlarged DB603E/G supercharger and with a rated altitude of 7.300 m.
Judging from the power figures listed above, it would seem the DB603AA fall inbetween the A and E model, offering a higher critical altitude than the 603A at the cost of somewhat less power on lower altitudes.

Now, was there any other differences between the DB603A and DB603AA except the larger supercharger?
Also, was the DB603AA a “new-built” engine as such, or was it a modification of excisting DB603A engines/blocks? If so, could any DB603A be re-built into a DB603AA, or was it only the final series (DB603A-2) that was possible to modify?
Data on the 603AA seem very hard to come by so any input is most welcome!