Thanks for the information, Hotshoe36. Gives me more to think about. I've been thinking about another gear after driving my late model 1 ton SM465 for a while. It has a Dana 70 in it, so rear end ratios shouldn't be a problem.
Probably the reason I have been thinking about a 5 speed with OD fifth is that my last three cars have been a 1990 Honda Civic Si, a 1990 Toyota MR2 and a 1990 BMW 325is. (I really hadn't noticed before that the years were all the same.) After those three cars, I'm pretty used to having more than three choices for transmission ratio. I guess that five speeds are necessary in cars like these to make up for a lack of torque, which is not as much of a problem with a Chevy six cylinder.
I'm really going to end up with two slightly different problems. In the late model I'm not comfortable with the engine RPMs at highway speeds. It has a 350 4bbl in it and gets about 13 mpg when cruising at 50-55. I live in a hilly area and will have to shift down to 2nd fairly regularly. I can live with that, but the large ratio difference isn't what I am used to.
The 1951 4400, which I haven't driven yet, is probably going to have a really steep rear end ratio with transmission ratios similar to the SM 465. The difference is the engine.
I may put a slightly smaller engine in the late model because I don't do much heavy hauling. The 51 has been upgraded to what looks like a pressure lubed 235. I'm still considering other options, but I think it might end up with a 292 I6 in it. (Unless I can find a cheap Jaguar 4.2 liter engine/transmission somewhere.
I guess my first steps are getting a tachometer and getting the '51 into my back yard instead of theirs.
