Hi SU, you may well have a b20b, they started using them in the 220 wagon about 10 cars after mine was built in '68 they came in many if not most sedans imported to the US - all the way up to the FI, so there are a lot of them.
The Cast Iron manifold was a tuned manifold 4 into 2 into 1 and the exhaust end of it is superior to many headers sold currently, just don't run dual exhausts as it screws the scavenging up, (I run 1 2" pipe all the way back and that works well).
People even hack the intake parts off and just use the exhaust side of these things!
What is inside those air cleaners? inquiring minds want to know!
Cheers!
Dave G.