Quick Driveline Question, Old Vs. New...

I went from a C4 to a T5 about 20 years ago. One of the best improvements you can do for performance and drivability. You wont gain much in a newer rear end other then disc brakes and gear ratio options.

I wouldnt say a late model rear end is easier to work on, but if you have a 8 or 9", you can set up a second 3rd member with differnt gears and swap them in about 20-30 minutes.

4r70w, 3k stall converter, aluminum driveshaft, 8.8" rear destined for mine. I wish it was road worthy so I could report how much I like it, but for now I'll just dream. Reasons-wanted o/d automatic, got the explorer rear basically free, just swapped some labor(MUCH cheaper than a 9"), I liked the fact it has the "big bearing ends", disc brakes, and lighter than a 9".

I had a T5 as I was looking at less rotating mass and drag on the drive line. As far as straight line driving, not sure if the T5 would have ever been faster than the C4. There is probably more potential, but I don't think I would ever get to the point where my driving and all the other suspension was at a point where I would have realized the potential. I did pull it on my motor swap and went with a TH400, probably even less efficient than the C4, but this build will probably be at the upper limit of the C4. When I upgrade next time I will have room to grow. I wish I would have thought about this the 1st time, and save a few thousand dollars. It would have been more efficient to go with the TH400 the first time in terms of money spent.

Also, I do have a Strange drop out 12" rear in that fits in a Ford 9" housing. It is more efficient than the 9", and stronger than the 12 bolt. You also get the other benefits of a 9" (ease of gear change, etc.) and I can put a 9" pumpkin in my rear end if I wanted. If your not looking for every little bit, probably not worth it, but an option.