That's not much of a problem, Most stealerships should know what engines were used in what cars during which years. Also the engine has to be out of production in the year the vehicle was made. If you place a 350 engine (from an 88 vette) into your 92 Blazer you won't be tested as a hotrod, you will be tested as a 350 engine and have to pass 1992 350 emissions due to the 350 still being a production engine in
1992. If you install a 283 into the same vehicle you will get the hotrod test as that engine was last produced in 1967 (?) or so.If you install an engine (say 350 again) into a ford, dodge or jeep you will be tested as a hotrod as (for the most part in the last 20 yrs.) Jeep hasn't used the GM 350.
Another way people try to beat the smoggers is to install a newer engine then whats in their vehicle, swap out their 1990 4.0 for a 1998, in this case the test is still done to 1990 standards (unless you shoot your mouth off at the testing facility).
Snow ... think I'll install a 283 in the 89 Caprice wagon for hotrod status .. lol