Pretty sure mine is a Ford Silver Calcium 075 Size 500A.
Only the 1.8's and above need the 075 if memory serves me right.. - 063 on 1.6's (petrols, mind. the Diesels need 075+)
Anyway, no issues with misfiring since it's relearned after air filter replacement. Running about what i'd expect. I noticed a bunch of oiley gunk on the bellhousing, a key sign of a rear crank seal or a d/s seal. Hoping it's engine oil and I can deal with it rather than transmission fluid.
There's also a whole bunch of rusty, ugly looking parts on the front and rear of the car, driver chassis leg is looking ugly, may be able to "protect it" at best. Nothing looks urgent though... Hope it survives the miles i'm going to be putting on it.