I've been asking around a bit about this topic.... still can't seem to get a specific answer....

If I have a smog exempt car (1971), but I put in an engine from a 1990s car and a cop pulls me over, could I get busted for having a totally different engine in there?

 

That's gonna be a cali-specific question since you have to deal with CARB. I know that in GA the state doesn't care and there's no effort on their part to see that you keep them informed of what's under the hood. I would think that since it's a 71, it's not gonna fall under any of CARB's gotchas, but may.

 

Yup... Cali... strict rules, but a great place to be at

 

I am not a legal expert but I have taken several smog classes.

Let's say you had 1985 camaro with a 305 in it. then you put in a
1995 350. Since the new motor is not a 305 you would have to take
it to BAR and get it approved.

Now lets say you have a 1985 camaro with a 350 and now you put
in 1995 350 that is called updating and that is ok. 100% legal.

I am going to guess since this a Mazda site your going to have a rotary
car. r100, rx2, rx3, etc.... to be 100% legal with the r100 I think
you have to get some kind of exception since I don't think anybody
makes that motor anymore. With the rx2 & rx3 you could update
to another 12a. 13b would be considered engine transplant
( i forget the exact wording they used).

Now in real life if you have a car older than 1975 I don't think anybody is
ever going to bother you. Just don't sleep with the daughter of BAR
referee, judge etc...

 

Yeah, most people I run into don't even know what my car ('73 RX-2) is. Doubtful that you'd get pulled over and they would know that a 13B didn't come in a RX-2.. or R-100, RX-3, etc. Heh

As long as it doesn't look too far off stock I imagine you'd be fine.

Mike

 

Exactly. Don't move the firewall or radiator, and don't tub it. Outside of that, nobody would ever know enough to care.

 

found some info on this subject: hybridZ forum