I recently ran my carbureted 350 SBC ZZ4 through inspection here in Tennessee and got the following results:

Hydrocarbons (HC) 140.64 ppm
Carbon Monoxide (CO) 5.37%

Those results were on 93 octane gas, no emission controls, headers and free flowing exhaust.

You might want to check with your state's emission inspection department to see what levels are acceptable there.

Dan J