Thought I would post my progress during changing the gears in my 68 bird (some suggested to leave this work to pros and we will soon find out if that was good advice)

As a side note the reason for the change was there was an open carrier and 3.08 gears, I opted for posi with 3.90, mainly because I want to squeeze the most acceleration out of my weaker 400 until a future upgrade to the HO 400 and M21 trans,

Anyway here's what I have learned so far:

I decided to test the current gear install just to see how good of a job was done, and from what I could tell (on a rearend that was working perfectly fine with no issues) I tested the gear pattern, I will post a pic, I was not impressed from my research both sides were smeared edge to edge, and with barely any backlash measured ( I bought a gauge) I'm guessing that the pinion depth was set wrong.

I also tested the preload on the pinion gear, from some videos I watched people were tightening these with 5' levers and torque amplifiers, I used a lever style torque wrench and turned pinion nut, gauge barely registered. My thought no where near tight enough probably why the back lash was off. I was able to remove pinion nut with minimal effort from impact wrench

I removed the carrier, and boy was it locked in there tighter than [censored]. I tried removing with pry bar, wouldn't budge, I then put some wacks on the pinon trying to push it out, no luck, I finally got 4' crow bar worked in there and may slow progress but got it out. My guess over shimmed, there were two thick ones, not sure size as my battery in my gauge was broke but I will post shim size later, but again from some videos I have seen the carrier should come out a little easier.

That's It for now, please comment on any or all of these issues as I am learning as I go!!