[kyleb]

The exhaust I used was an old Robnell exhaust from the 90s. I am told by a reliable source that Ford used to use much better quality cats back then due to the poor emissions of the engines. Now the engines are much better with emissions due to the fuel injection and computer setup means they don't have to be so stringent.
I will find out what sort of a temp rise you should expect, just bear in mind a cat acts like a blowtorch just completing inefficient combustion. So you will see an appreciable rise.
I think if whatever cat you use lights off properly you will be fine.
Its more the tune and positioning of your MAF which seems to have more of an effect on Emissions than anything. I am told 400mm from throttle body is ideal to give the computer time to respond, with that being said mine passed, (albeit only just) with it about 100mm from the throttle body.