1964 C10, Air ride conversion/Overdrive

[Spec_Dragon]

I have a 1964 C10 that was stored in a garage for over 30 years by my Grandfather. I have done my best to keep it original but I want to do two things to it. One, I am looking for an overdrive unit. The three on the tree works fine but 3rd gear maxes out about 65 @ 3000RPM. In Texas that will get you run over. The second thing is the old coil springs are well past any useful load carrying capacity, not that I do any hauling with the original wood bed but the old girl squats and it is getting worse. I have seen advertisements of air ride systems to replace all the coil’s front and rear. Does anybody have any experience with these systems or have a better idea. I could go back to the factory springs but an air ride has a great appeal to me. This truck has been in my family since it drove off the showroom floor in Republic Missouri. I even have the original bill of sale. I started driving it in 1992 after Gramp’s went into a nursing home with 42K on it. She has been driven sparingly since then. I want to keep it as original as possible. The 235, 6cyl was rebuilt due to valve seat problems in Jan 2006. Other than that, nothing else has been touched baring normal maintenance. And I will answer this question before I am asked, I know it will.

101,753 miles as of 4/27/2006

Any sources or ideas will be welcomed. Pictures when I find my camera.