Will a 2.8 transmission bolt up to 4.3 engine?

No, a 2.8 transmission will not bolt up to a 4.3 engine. The 2.8 engine and the 4.3 engine are both General Motors engines, but they have different bolt patterns for their transmissions. The 2.8 engine uses a 60-degree V6 bolt pattern, while the 4.3 engine uses a 90-degree V6 bolt pattern. This means that the transmission bell housing for a 2.8 engine will not fit on a 4.3 engine, and vice versa.

In addition, the 2.8 engine and the 4.3 engine have different torque outputs. The 2.8 engine produces approximately 170 lb-ft of torque, while the 4.3 engine produces approximately 250 lb-ft of torque. This means that a transmission that is designed for the 2.8 engine will not be strong enough to handle the torque output of the 4.3 engine.

If you want to install a 4.3 engine in a vehicle that originally had a 2.8 engine, you will need to use a transmission that is designed for the 4.3 engine. You will also need to modify the transmission bell housing to fit the 4.3 engine.