the airbags do come in different diameters, I am unsure if your springs are smaller or if you have got the wrong bags.
If your springs are smaller, you could try a set from a firebird or maybe the mustang, measure your i.d. of the spring and the height of the spring (with the weight of the car on it) and let Air Lift know that info when you call them, I am sure they have something for you.
FWIW I laughed also, I just went through a stuation like this on my station wagon, and there is way less room to work on that than there was my T.