Out here they start with the gas cap. It's tested for pressure. The visual inspection makes sure all smog equipment is there. They are looking especially for the easy things to remove (EGR, EVAP canister, breather to intake, etc.) Any aftermarket parts that deal with exhaust before the cats, iginition, or fuel (like a supercharger) must have an E.O. (Exemption Order) number. The tag for this must be either a sticker located on the front radiator support or be metal tagged or engraved into the part itself.
There is an exhaust inspection. Every shop is supposed to do this but they rarely get very detailed with it. Any vehicle that comes with single exhaust may not be changed to dual exhaust. O2 sensors must remain in factory locations. Factory cats must remain in factory locations. Cat-Back systems are okay as long as they are not true dual. (On vehicles that came with single.) Dual or single in and dual out mufflers to different tailpipes are okay. The computer is checked for driving cycles. There is a minimum amount of run time that must be clocked since the last code-clear. They looks for DTCs. Also, they check idle electronically. Idle must be smooth and not fluctuating. The put the sniffer in the tailpipe. Emissions are taken at idle, 15mph, and 25mph.
I am probably forgetting some things. There's a lot to it.
Some shops will overlook little things like dual exhaust as long as everything else is in check.

 

holy ****... what are they... the fuggin sniffer ****'s??? damn that seems like way too much to worry about. all I ever have to do is turn on the headlights and blow the horn for them... 99% of shops in tx dont really care.

 

so are there any gains to the edelbrock headers? and there is no visual inspection in the motor bay.. like looking at the motor... or anything that they could do to make them think that it doesnt have a 4.8 in it?