I'm looking at buying a nice 74 j10 with a 360 and th400 with the quadra trac t case. I am wanting to swap the tranny and t case out and put a t18 in with a Dana 20 t case. What fabrication or other parts swapping would this entail? Rear axle, driveshafts? Any info would be greatly appreciated, lots of detail is great too, thanks!