torque converter question

this is not an A body Q, as it pertains to a D150 w/a slant in it. and 3.21s in the back.
and a 727. (yes I know how to tell the difference) the 727 stays.
IDK yet, if mine is a L/U version or not, seen them both ways in the mid 80s. if mine winds up as being a L/U, then this thread will be moot/ as the converter I have in mind, is for a non L/U version. If my truck is supposed to be a L/U version, the L/U function ain't working.

I will know as soon as I get the engine out, existing converter out, and see the input shaft.

the whole reason I ask, (and I don't yet have the old engine out, so I can see what I think is behind that shield) is that I believe my ring gear may have issues/ as sometimes I have weird noise while cranking, that sounds like bad teeth on ring gear. I have swapped starters so far, to try and eliminate that possibility. it still does the same, with the other starter I put in place. if it weren't for that possible problem I would not be worrying about doing anything with the existing converter. except to "run it". I think whether it is noisey or not on any given start, is where the converter stops when last shut off, and the starter has to take off from along the gear, on the next startup.

truck seems to drive OK, but is a dog off the line. (engine currently being built, will help solve that problem) 1st Q, anyone know what stall would have most likely come stock in the truck? FYI it's an '85.
I have come across a B&M "Tork Master" for what seems a fair price, not much more than what a stock "rebuilder's" converter would cost (I think anyway, I haven't bought a converter for a 727 in a few years) Certainly not $4-600, like most aftermarket 727 converters I see, tend to go for. They are advertising it as being 1900-2100 stall, and "not for big block/supercharged application". B&M's catalog number is 10416, that I am considering.
How would this converter be, for that application? I don't want a 12" like many 727 converters were. What would determine whether this would stall at 1900, or whether it would stall at 2100? I know there are a few determining factors here but do not remember what they would be.
If my fears do come true, and I have to replace the converter while the engine's out, I want to go with an 11" or maybe a 10" if there is such a thing, for a 727. but that is one thing that I have not been able to find, is the converter diam. for this unit. Anyone know?
as far as the standard transmission shop "rebuilder's special" converters go, I remember from past experience, that for most body/engine/trans combos there was a "low stall" and a "Hi-stall" version. How low is "low stall", and how high would "hi-stall" be, if I go that route?
Any quality issues to be aware of with B&M?