The 200r4 is the same length as the th350 and uses the same yoke. Your factory driveshaft probably slipped right in.
Not sure about the strap vs the u bolts . I have had both on 10bolts. The 12 bolts usually have the straps.
I always use the ole reliable, sorry for the word but, ford type f fluid. That's what the trick shift fluid is and cheaper, not much, but it is.
Run it in all our th350s and the 400s.
Best case scenario you will need a "combo" u-joint. From the 10 bolt big cap to the 12 bolt small cap.
Some find it necessary to cut the 10 bolt driveshaft or replace it.
If the car is a 10 bolt but has a th400 in it, the combo joint is all you will need. But most small block equiped Monte Carlos were th350s.
Everything else is the same.
Check the connectors at the bottom of the columns. Compare the wiring colors and locations of each wire. Most likely the wrong turn signal switch in the new column.
Depends on which 10 bolt you have. If the 8.2, I would use the 12 bolt. If the 8.5, then the choice is yours. The 8.5 is just as strong when built as the 12 bolt.
I have a 3.31 gear with detroit trutrac in my 496 70 SS Monte Carlo "Big Red" and the same exact rear in my 71 402 Monte Carlo "Barn Find"
Big Red has seen more track time than street time. The 496 loves the 3.31s
Sorry, I agree with you thoughts but you can't beat a trutrac. So simple and so strong! I have broken to bits every posi you mentioned plus a moroso "brute strength" posi and a strange posi. Believe me on this one, purchase the trutrac and you can thank me later. No clutches, no special additives, just simplicity that works.
You are correct about the Flint cars not having a build sheet. None have been found. Sounds like a very well optioned Monte. The passenger side mirror was not an option. Most likely a dealer installed part or former owner installation. Pics???