A misfire under load is often suggestive of an ignition or fuelling fault. You can check the performance of the fuel pump to see that it's delivering the volume of fuel it should, but don't ignore things like dirty fuel filters as a cause of poor fuel delivery.

That said, this engine is particularly susceptible to failures of the ignition coils. In fact, most mechanics who know their way around this engine will suspect faulty coils before anything else. It's not a terribly expensive fix even though there is a separate coil for each cylinder, but nine times out of ten, this will be the problem in a misfiring Falcon or Fairmont. The other piece of advice is to ensure you only use the genuine Ford ignition coils rather than a cheaper, knock-off coil.

If you talk to suspension specialists like Pedders they will tell you it's a common problem. The springs Ford used are quite long and they're compressed into a small space so they can distort and foul the strut as yours has done. You can replace them with factory originals from Ford or use aftermarket springs from someone like Pedders. They cost about $190 per set of two springs, or about $390 fitted with a wheel alignment. I don't like your chances of getting new springs out of Ford.