Greg, if you could, can you take a couple of photos of the nacelles please and email them to me. I have the 1/72 set but it only came with two nacelles, I think the ones I'm missing are the ones which have the additional air intake at the rear end (the set is buried in the stash and not easily available at the moment). If that's all the difference it shouldn't be that hard to make up two new nacelles.
Robert