Just trot down to your local motor factor with a sample of any offending, bust or suspect parts and let them do a comparison with similar bits from both Fords and Mazdas of that era, I'm sure you'll hit the jackpot most times.
The owners clubs will probably also have a list of part numbers that fit either vehicle, so if you cant get the part in a Mazda box you can get its equivalent as a Ford or pattern part.
Also, don't forget the speed or generic shops that sell things like the HT leads in singles where you just build up the set from their rack of different lengths for example. Same goes for herds of bits, the manufacturers rarely made one part for one application only, you just have to track the damn bits down, then when you have the OEM for each system, you're half-way there!
