I have a 99 Civic and just bought a universal catalytic converter to replace mine since it was clogged. It is the same diameter on both sides and does not show an arrow to know which way to put it on. The only difference is when you look inside one side has numbers on the screen the other side is just screen. Is there a certain way I should be putting this on?

 

The end with the shape that's almost a triangle goes in the back

 

-take off the old cat
-match up the new cat with the piping under the car. One side uses two bolts, the other 3. -There's no way you can mess this up

 

Usually a universal cat. converter has to be welded into place.

 

I know it has to be welded, I am just going to put it on there and if it runs like **** I will pull it off and turn it around. It seems to be identical on both sides.