what year for no cat

[Josh]

If you are using your engine in a kit-car, which you are , then as long as the engine is pre Aug' 1995 then you do NOT have to use the cat, even if it was running one in the production car.

This is because it took a while for the kit-car regs to catch up with the production car regs, I believe all production cars had to run cats from the late 80's onwards.

So your '93 engine will not need a cat, I searched long and hard to find a 93 mondeo for that very reason...