Ok, I have a few points to mention.
I looked over the photo's you posted. The engine in the truck is the most probably not original but later series Maxidyne 237 HP (ETAZ-675 or so, other guys will correct me). My guess is based on presence of the water/oil heat excheanger (cooler) at the left side. B's had turbo engines too but without it. Air intake pipe from the air filter to the turbo looks custom (home)-made. Also someone converted original air operated wiper drive with electric motor. Both facts may be even seen positive. At least the engine is more powerful but very similar to the original ENDT by the look so I wouldn't sorry about the fact.
If the truck had 9-speed tranny with two sticks I'm pretty sure you will have quite enough "fun" shifting it. At least in the beginning. The 2nd stick is a splitter. So you start in 2nd low than shift to 2nd high (with that 2nd stick) than you have to get 3rd low so... you shift both main from 2nd to 3rd and the compound from hi to lo. At the same time and without clutch! I may be a bit extra emotional on this since the most American guys who drive a vintage truck count that action as simple as apples. But an avarage European person who's skilled to drive a car with synchronized mechanical box finds himself in a total nightmare when tries shifting that unit. I don't want to spread too extensive description but just mention one more fact. 5th main (the top gear) is right front from you. Not right rear as in a car. So you shift the main stick left front-left rear- right REAR and than right front. That's just an addition to the no-clutch (or double clutch) shifting using two sticks.
Ok, further on. I would like to see the housing of your transmission from under the truck. And the front axle beam too. Since I have an interesting guess. At least the axle beam looks familiar to me by what I can see on the front truck's picture. And that's not an axle typical for a B-model.
Of one more interesting point is the rear axle ratio. It determines how fast you can go with the truck (using particular transmission and the drive wheels size for sure). If you look at the differential housing of each rear axle at the front area to the right of the propeller shaft flange you could see two data tags (plates) attached with rivets. Clean out the lover ones (but sure better both of them). There's a script "RATIO" on the lower plates and than 3 digits (6,34 or 7,33 or so) are stamped in. My bet you will find 9.02 there. But I may be wrong.
Also your truck has cool looking heavy wheel hubs for 20" tube type tyres. The hubs are not typical for North American market, my guess they were a special order for a certain East customer. The rims are split rims made as 3 portions. They must be reliable enough to drive safe if mounted right. Many people may say they're bad thing and nobody wants to work with them for tyre installation. But on my mind they're suitable for self service and are definitely a nice sample of the older days engeneering. So I would keet them if that was my truck. Sure it's yours so you're up to the choice.
The tyres on the FR axle look like made in Russia 12.00R20 or 11.00R20.