transfer case/diff question

[59Apache4WD]

I have a "frankentruck", it's a 59 Apache, but has 74 k10 running gear. GM corporate 12 bolt rear axle/diff with new Eaton Posi diff 3.73 gears. I know that the transfer case in a NP205 that leaks a little, and the front axle is a Dana 44, that at least originally had 3.07 gears. Can I check the ratio of the front diff by lifting the front end off the ground and turning the driveshaft and counting the rev.s of the wheel? I don't know what I need to know about how it's all 'sposed to work together. I heard that the front and rear diff.s are supposed to have the same gearing, does that mean that the output of the transfer case is the same to the front driveshaft as it is to the rear - 1:1?
I'm hoping to find out why when I try to put it in 4WD/low it makes ugly noises from down below,it may just be that the hole in the floor isn't big enough to let the transfer case lever move far enough forward to be completely engaged?
Any answers and or advice greatly appreciated!!
Jeff