I'm in NY, and my truck don't have any cats. And I have to get some in before next inspection. I have true duals, so do I just get two high flow cats and weld them in?

 

If you want to retain true duals - Yes.
OEM V8's had dual inlet, single outlet forward cat and then a single in - single out aft cat.....

 

Be sure to check you local laws before you buy your cats. Some places don't allow certain types of aftermarket cats. For example in California you must use a CARB certified cat. If I recall correctly NY is fine with high flows but be safe and check with an inspector before wasting money. Personally I would add a crossover or balance pipe for better performance while your at it. Which reminds me, you may also have a crossover requirement for the O2 sensor. So again check to be safe.

 

And what a bout the sensors?

 

You will need to have the factory sensors in place for your year and motor. I don't know if they will require a balance pipe so the sensor can read both sides. And you will probably need the secondary air system attached. Again I don't know the laws for your area, I'm just giving you things to look for. Federal law says you can't remove any smog device so they will probably look for those.

 

I have hit almost the same issue with my 86 bronco i am using for winter. Mine is old enough i do not have sensors to deal with so i am just patching a cheap cat into my exhaust. NY requires them to be CARB certified catalytic converters and also has made it illegal to sell or purchase a used one.

This one is legal in NY, at least by my research it is.
http://shop.advanceautoparts.com/web...rchTerm=80707+

 

I have no cats...I went to 2 shops in MA before I cut them out and said what do you look for on an emissions test with a 91. They said it doesn't matter as long as they see tail pipe. They didn't care about sound or smell.

 

I wish it were that easy in NY, but next year big brother wants camaras on the computer. Otherwise the shop I go to wouldn't care.

 

NY is a pain that way. I know of at least two shops where i used to live that have stopped doing inspections all together because of the new rules that keep being added. If NY didn't require them i wouldn't bother at all with them, especially on my bronco. My 95 f-150 has the factory exhaust so i do not have to worry with that truck.

 

That gives you an idea what exhaust shops know. They know welding. Its illegal in all states to remove cats. That is a federal law. Now that doesn't mean all inspectors look for what they are supposed to, but if you are trying to be legal and don't want to have to worry about wasting money, tickets or dealing with gross polluter registration, then check with your states emission board. No reason to waste money on fixes that don't meet the standards. I can tell you California's and federal laws but that took me 6 months of school and I still have to look things up. There's no way I can remember all other states for every car.