Well they started in 1990 I guess with the first B18 Integras. 90-91 was ODB-O, 92-93 was ODB-1. After that was B18Bs I think which are probably ODB-2. The head can come from any VTEC B-series like the B16A, B18C (GSR or Type-R). I think, not positive. But you have to use certain internals to make it work right.