Datsun PU gears

[greengoose]

I bought a Dwarf car that was built a while ago and it has a Datsun PU 10 bolt rear end. I have 3.70 and 3.90 gears. I am not familiar with all the terminology but I am trying to find 4.11 and 4.30 gears. Nobody I race with has a Datsun rear end they all went to Toyota a while ago. Here is my question.

Is there any way to tell what type of gears an old Datsun Pickup truck has. We have a salvage yard near me that has several Datsun PU ranging in year from 1970, 1975, 1976, and 1981. Is there a certain year or model that came with certian gears? On the original pumpkin, is there any kind of stamp or markings that will tell me what gears are inside. If I drop the 3rd member can I count the teeth and will that tell me. In my extra third member I counted 36 teeth and it is 3.90.

At the salvage yard we tried to turn the tires and count the drive shaft but not sure if I was doing that right because I came up with different numbers. On the two 1976 PU's I turned the tire ten times and counted 22 turns of the drive shaft. On the 1975 I counted 21.75 turns and on the 1981 I counted 19.5. Don't think I'm doing something right.

I just want to find out what gears these old Datsun have and if there is a way to identify the gears by year, model, or amount of teeth. Any help would be greatly appreciated. Thanks

Kenny