[rsimoes]

I got it! I found the air filter that fits almost perfectly! It is the NAPA one:

NAPA 6094
WIX 46094 (they make it for NAPA)
Fram CA140
Purolator A12283
AC A629C

I have the NAPA one, though they should all be the same size, I don't know if they vary a bit.

The NAPA 6094 measures: (inches)
8 & 1/16 diameter and 2 & 1/16 high.

The Stelling & Hellings Air Cleaner housing is actually not 8.5 inches in diameter, it is 8 & 1/4 and the foam element in there is 1 & 3/4 inches tall.

However, it may be too tall in some applications. If so, you may have to use the K&N that is about the same height as the OEM foam:

The K&N E-2570 is:
8 and 3/16 inches diameter
1 and 7/8 inches tall