Will a 2.8 transmission bolt up to a 4.3 engine?

hgihly depends on the car. If the engines both came from the same cars it probably will. Its doubtful an manufacturer would make it so they couldn't be bolts to the same tranny, or else an engine upgrade would require a dif tranny. If It's a early 90s gm car, I'd say yes. We need more of a description.