ok here is wat i have learn from experince word of mouth and from working at my shops. As california smog laws goes, cars that are 4 year or less dotn' have to smog till it is 4 years old. that means current any car bought on 11/5/98 don't have to be smog as of yet. That means Tegs, Civic and so forth dont' have to meet any smog requirement for a while. For the rest of us older Hum ho

we do it every two years. Most of these guys start there swap right after they smog. that means two years with teh fun car till you either (1) return to stock. or (2) the cheaper of the two] is to pay a smog guy off. slip an extra hundred or two here and there. this method is illegal or the two. As someone had also mention, ther is a way to get your car legalied after a swap. Cause come on people rebuilt old cars and they aren't using the old engine now are they. And some engine just blow up, so people get it checked out.
I will talk about the two engine type, first is JDM engine. With the JDM engine, when they get to the US, they actually have to have a reason to be imported to the US. most ppl get by, by sayin that they are being used as a decortive peice that sites in a show room or there living room floor.

If you were going to install it into a car, tons of paper work has to be done to get it to meet US or cali smog legalization.

So it will be much easier to swap in a USDM engine. and yes JDM engine can pass cali smog, but it that state ref that kills people.
Ok now on to the USDM engine. I believe cali law states that you can swap into your car and engine that is the same ages or older. So most people look for older engine if not the same ages one. But come on wat 95- ppl would want a engine from a 5th gen. those are OBDII. Then next part of the law that i have heard about is this. The engine that is swap into a car has to be the same Liter or less. Meaning F22 can't go to a H23, but a H23 or F22 can go into a H22. I dont' know how some old mussile(sp) car get pass by puttin in a Big block. but this is what i have heard. ( a civic with a B18 is way illegal).
I am goin to mention hybrid engine in here too. I belive that if you put a vtec head on the engine, it is ok. cause the block will have the same Vin number as the car, and ther is no vin number on the head. seeing as that is how it is. i doubt all cops or lil smoggie know all the engine code. so if i built a H23 vtec. it wont' be notiable. or for the tegs a Ls/vtec, correct me if i am wrong but the LS are B18 any how rite?
i think i got the engine parts cover. Being a San Diego resident and have friend with insane motor swap i have heard all the crap about it. I got buddy who has a H22 in a civic coup.

yes it is fast. But well ther was a Street racing bust a while back. they went to the gas station and had all the cars open ther hood. It like so many tickets it is insane. we are talkin about 13 different infraction

this will discourage ppl from doing swaps. But my buddy havin a h22 in his civic was let go cause he had the fastest and cleanest swap out of all the b16 civic

(that mean H22 are better ) . I also have a buddy po.com that got a fully built turbo prelude. cops did a barricade to the drag strip and he had his engine hood pop. they sent him to the State ref. but he got out of it(thankfully). So ther are just ways around the state ref.
Ok here the biggie. If you are sent to the state Ref, your ass so out of luck. That means one let your car be a trailer queen. or two return your car to stock, or try to get as many legal parts as you can. THere is no B.S. with these guys. I wil say right now that i went to go have my car smog a while back. The guy that did it was like chilln. i was stock mind you. All he did was pop the hood, look for any crazy mod (stock really) and just hook it up and ran the car. he didnt' check no Vin number on the block to match the car. he didn't bother to check it i had the right engine. type so most places in socal are ok, you got an engine, no turbo or SC, it looks stock. and it fits the car type ok let run the test.
So i hope this clears up some air on engine swap that people do. Unless you are caught, no one will know. so if your in cali, stay out of the street races and you wil be fine

i should mention taht my buddy has a TT supra that is so not smog legal, but his car got to pass smog soon, so i know he goin to pay some1 off. either that return it to stock for a few days and smog it and go back to being a 400 whp BPU supra
And all this info is what i belive, i could be wrong. IF anyone heard anything different feel free to correct me.