Does a 305 bolt up to the stock transmission on an 1983 GMC S-15 with 2.8l V6?
No, a 305 Chevy small-block V8 will not bolt directly to the stock transmission of a 1983 GMC S-15 with a 2.8L V6. The bolt patterns on the engine and transmission are different. You'll need an adapter plate or a transmission designed for the 305 to make it work. This is a significant engine swap requiring more than just bolting things together.