Mazda did not use a V6 engine in the 1989 B-Series pick-up. Only two options would have been a 2.2 liter and 2.6 liter 4 cylinder. A V-6 engine was not available until 1994 when Ford began producing pick-ups for Mazda in the U.S.
According to Mazda 3's own specs, the car has zero towing capacity. That is, Mazda does not recommend towing anything. Compare this with the Toyota Corolla, which has a 1500 pound capacity.
Mazda does not supply a rated towing capacity for the Mazda3, probably for legal reasons. Some people say you can bolt/weld on a class 1 hitch, and speculate that it should be fine for towing 1000...
The towing capacity on those cars depends on the year and transmission. the newer the car the bigger the load it can haul, but I wouldn't use it to haul much more than you can stuff in its trunk and...