A D16A is a D series engine, with 1.6 liters, the A signifies its a an earlier model, but there should be a trailing number as there are different models with different HPs and specs...

D16A1 Acura Integra 1986-1987
D16A3 Acura Integra 1988-1989
D16A3 Acura Integra 1988-1989
D16A6 Honda Civic Si/CRX Si 1988-1991
D16A6 Honda Civic EX 1990-1991
D16A8/9 Acura Integra 1988-1989
(For specs on these engines go here: http://www.integra.orcon.net.nz/engines)

And the B16A (the 1 I was talking about is)
B16A 1.6 16V DOHC VTEC PGM-FI 1595 160hp@7800rpm 111tq@7300rpm 89-91 Civic SiR

Not sure if u know this, but reading Honda engine codes, the first letter is the series of engine... The next 2 numbers are the displacement, so a D16 is a D series 1.6 liter engine... A B18 is a B series 1.8 liter engine... An F24 is an F series 2.4 liter engine... The next letter tells the specifics of the engine, and the next number after that tells even more specifics... Note that the JDM engines dont have an actual stamp on the for the last number... Like a USDM B16A3 (from a Del Sol VTEC) would be stamped as such, a B16A1 (as its commonly reffered too) from a CRX SiR would be stamped only B16A... The 1 is just added by everyone to distinquish its the preOBD with cable tranny version of the B16A...