I've googled this to no avail.... I just picked up an NOS brake booster, via another Mopar site. It appears to actually be a dealer-install retrofit kit" for something that originally came with manual brakes. Came with booster, vacuum tree for intake manifold, a length of 3/8" vacuum hose and a pair of squeeze clamps for that hose. Within the instructions included, (of what I can make out anyway, age hasn't been good to the included instructions) it shows said vacuum line routing for both a B100 (van) and a D100 (pickup) for a slant 6 as well as for a smallblock, for both models.
It has 2 studs for a master, which had me thinking early '80s. my 70s trucks (as I can remember) had 4 stud master cylinders. The dealer tag on the original box is totally unreadable.
I have a used booster from a 1987 D150 here, and the contour of the firewall side of the booster is different, as is the pushrod that connects to the pedal/ oh yeah, the instruction sheet does say to contact dealer parts counter for a different brake pedal assy/ as I guess those were different from a manual brake model.
On the original box the PN is 4131299. can anyone give me fitment information and/or interchange/supersession info? I bought it hoping it would fit my 85 D150.

nobody? I tried Google. Dead end there.

Do you have a pic Don? Looking through my pictures for 2 and 4 bolt masters it kind of seems to be mixed up.
Had a 75 sb with a 4 bolt and a 75 bb with a 2 bolt. Have another 75 with a 4 bolt.
Have three 78's with a 4 bolt but had another 78 for decades that had a 2 bolt.
Had a 79 and a 80 both with 2 bolts.
Had a 73 with a 4 bolt but when I get to the shop I need to check my 73 W200 cuz I think it has a 2 bolt.

I'll try to get some. I'm not good with posting pix online.
And being the application instructions say B and D100 (not 150) I figured it's for something older but then again all the 70s ones I have had were 4 bolt MC but being this is for a 2 bolt MC that says "newer" trucks, meaning years they sold both 100s and 150s. (Though there isn't much different between those 2 series of truck haha)

This is the one you bought isn't it? https://www.fortrucksonly.com/truckforum/threads/nos-mopar-power-brake-booster.6081/

Yup that's the one. Looks good out of the box.

number does not cross in napa look up. but shows it as a brake package that has been discontinued from mother mopar, the fitment is 1979-1983. probably truck.

I'm really bad at taking pictures but it looks like the one that was in my 79. My 80 also had the same. I've never owned a 81-91 so don't know about those.

My 78 D300 360 had a 2 bolt but have a smaller booster as did my 75 440 D200.
Actually my 78 D200 400 has a 2 bolt so it looks like the smaller BB boosters were 2 bolt and the larger SB boosters were 4 bolt up through 78 and then went to the aluminum 2 bolt master in 79.

The ones in a 3/4 and 1 ton are different from the typical booster in a 1/2 ton. The 3/4 ton,1 ton and "big block" 1/2 ton trucks used a smaller diameter tandem booster. 1/2 tons with /6 or small block used a larger diameter single diaphragm booster.
Big block apps needed the tandem booster because the single diaphragm version and the big block valve covers competed for space back by cyl 7. And as I (vaguely) remember ones with the tandem booster took a 2 bolt master as well.
I bought this nos one because of all the talk about how difficult the boosters for these trucks are getting to find these days, usually sending your old one to Cardone for rebuild and return is the next step to obsolete/unobtanium. And I've seen guys on the forums saying that they were having trouble getting even lowly Cardone to offer this service for these particular boosters. So it was a get while gettin'was good situation. I have this 85 and my son has his ramcharger neither of which we plan to part with anytime soon, and I hope this isn't my last D/W truck. I'd much rather have a D/W series Dodge over the more current models.
I've had 94-02 and have driven newer /and simply "no thanks". So if I can stockpile parts while the getting is good and at reasonable prices I'm going to.
My son just bought a '17 and spent more than I did for my 1st home, and more than I have spent cumulatively in 38 years of being a licensed driver for paper thin sheet metal /, too much plastic and too much electronics for my liking.