before you throw that bitch back in; i might like to mention that the smogs down here don't care at all about it.
a b20 block looks no different from a b18. the smog guys generally don't care about what engine you use. wait let me rephrase, they don't know the difference. serious shit, the only time some one says anything about it is when the b20 uses an obd2 valve cover and they notice the weird lines that don't match up with the obd1 intake manifold or they fail you because you used a breather thingy on the valve cover line.
personally i would just install an ugly ass obd1 valve cover assuming you have an obd1 intake and send it out for smog. they probably won't know the difference.
the b20 will pass b18 specs on smog.
if by some chance you fail the visual. it's okay just go to the next smog store that seems busy and they'll rush your shit out even quicker. I.E. not bother buy look at the engine code. if you still have fear. just dab some oil on the engine code and some dirt to cover the shit up. i don't know a single mechanic who would purposely touch grimy oil to look at an engine code. (i would know i work at a Major Repair facility which does Smog)
HOWEVER if you plan on getting your shit BAR'd which means to get a certification to state that your engine is permanently swapped with a different engine from another veichle. you would have to send that to the state referee board and they know their shit. you will not get a validation sticker through this means. as it is an illegal engine swap.
so geting a california sticker won't happen. but passing smog to register the bi annual thing is a very simple process.
edit: i want to mention one more thing
it's not like it's as bad as people say. just because you don't pass doesn't mean they'll give you a fine or impound it or anything. they just let you be on your way and not let the registration fly. that's all