Clay,

Very early 240's had ratios of 3.73, 3.90, 4.10, or even 4.30 to 1 depending on engine size, type and transmission. Manuals typically had the 4.1 or 4.3. Later models dropped the 4.30 and eventually the 4.10 and just used 3.54 or 3.73 with the type 1031 rear axles and/or 3.73 or 3.91 with the auto box. Confusing ain't it! I think you're right about the GT's. Can't read the ratio off the plaques on mine so not totally sure about the later ones. I seem to recall that mine ('81 model) has a 3.73 because of the increase in wheel diameter from 14" to 15" but I could be wrong. A 4.10 instead of one of the lower ratios would give better acceleration and more in-gear flexibility at the expense of increased noise and (possibly) fuel consumption and it would make the speedo inaccurate. I'd like a 4.1 in my GT - overdrive is really more like over-over drive and is pretty useless on a hill (which we've got stacks of) and/or with heavy loads.