The reason you will always get different numbers is because the Truck model(reg cab or super cab) matters
Engine size matters
Rear axle ratio matters
2WD or 4x4 matters
Auto or manual matters
Weight of the truck, passengers and cargo in the truck matters as well
Ranger or Mazda won't matter, so Ranger numbers will be the same if all other things are the same, and will probably easier to find for a 1994 model
So 1994 3.0l engine with manual trans
2WD or 4WD?
Regular cab or super cab?
Rear axle ratio, look on drivers door tag and go here:
http://www.therangerstation.com/tech_library/axle_codes.shtml
Then look here, 2WD regular cab models:
http://www.therangerstation.com/forums/showthread.php?t=119488
GCWR = Gross Combined Weight Rating
This number is the weight of the truck, + driver/passengers + cargo, + trailer weight
GVWR is NOT the same, thats just the truck only weight limit, truck weight + people + cargo in cab and bed
So if truck weights 3,000lbs, and there are two people, say 150 each, you will be at 3,300lbs, and say 100lbs of gear(cargo) in the bed, so 3,400lbs total
If GCWR for your 3.0l 3.73 manual regular cab is 6,000lbs
Then you do this: 6,000 - 3,400 = 2,600lbs available for trailer weight
If GCWR is 5,000lbs then - 3,400 = 1,600lbs for trailer
This is why there is no general number for 1994 B-3000 manual trans
And these are "may" numbers, legal limits, not "can" numbers
Can is the ability to do something, May is permission to do something
You CAN rob a bank, you MAY not rob a bank
So you can tow more than legal limit, your truck will have that ability, you just don't want to get weighed or have an accident.
And some states require trailer brakes on trailers above a certain weight so you need to check on that in your state and any state you might being pulling a trailer in
And your trailer hitch also needs to be rated for the trailer weight you will be pulling