833 OD transmission

If you're getting new blocker rings, you have to be real careful that they are perfectly round, and that they grip the brake cones with only the tiniest bit of pressure. I put my gears in a lathe and give the a couple of swipes with 120 emery cloth.
If reusing the old ones;
use second gear and try every ring on it, selecting the one that brakes the best, from among the rings that sit the highest.
For the input gear, select the next highest sitting ring, but it doesn't have to work all that well, because about 90% of the time you will be granny-shifting it.
The crappiest one can go onto overdrive.

And the big tip;
When you are jamming gears, pretend it's a 3-speed. Cuz if you ever forget; ZING! that gear is in a bunch of pieces and no one knows how many other gears those parts are gonna take out, on their way into the bottom of the case. I broke two of them with a 318, and another with my 360.. Get yourself a spare trans, while you can still get one cheap. Later, under the gun, you will pay quadruple or more, just to get it into your driveway.
Remember; it's a 3+1.
It is NOT a 4-speed.

If your case has a floating cluster-pin; don't forget to seal and install the welsh-plug into the cavity at the front of the cluster-pin,lol.
Install the right speed-O gear for your gears and tires.