I would think a properly fitted carburetor would comply with emissions regulations. During the manufacturer changeover from carby to EFI here in Australia, carburetted engines used specific emissions control hardware primarily mounted on the exhaust manifold to keep it on par with the emissions regulations and motor vehicle standards act.
EFI just used a standard manifold.

The way I see it, if you can have that engine converted to carby and meet the standards of the factory system which was in place the year before, you shouldn't have any problems. Vehicle inspection from a certified mechanic would probably be the next best thing.

I'm guessing it also doesn't have a catalytic converter, you should be fine there but it could be worth having one fitted at a later date just to keep on Mr. Plod's good side. (high flow cat, to avoid excessive exhaust back pressure from a low power engine but is also cheaper than factory systems)

Click to expand...