This job was slightly harder than it should have been as I didn’t know that there are two types fitted to the twin cam and I got the wrong ones but had to modify them to fit. When you go down to your breakers to get your fans make sure you get the ones with shallow fans as opposed to the deep fans. The shallow fans fit straight on but the deep ones do not as they are so deep they foul the pulleys etc. Below is a picture of mine, you may notice one of my fan motors is of an Escort (left) and (the deeper one on the right) is the twin cam one.
I do hope this is of some help, I am no great writer, just an engineer who done this mod himself, please let me know if I have missed anything and I will add it in or change.
