I have an 84 camaro berlinetta junking my 305 and buying a rebuilt 350 that came out of a chevelle. I dont know a whole lot about engines and i hear things like big block small block and wondering if it is as simple as pulling my 305 and dropping the 350 and having everything bolt up correctly. The last thing i want is to buy this engine and have to sell it because it cannot work in my car.

 

Both are a small block the only difference is the internal displacement.
they will swap with no fabrication needed.

 

If the engine came in the Chevelle from the factory, it will have the dipstick on the driver side. You won't be able to use the Chevelle exhaust manifolds, and the Camaro exhaust manifold and the older 350 dipstick tube will try to occupy the same space at the same time - and that never works very well. Headers solves that problem. Some have carefully bent the dipstick tube so it clears the exhaust manifold. Others have used a Lokar flexible dipstick.

You will need to use a flexplate and starter that came together - either your 305 flexplate & starter, or the larger Chevelle flexplate & starter. This may lead to problems, as the Chevelle engine might not have the starter mount holes that the 305 starter needs, and the Chevelle flexplate may not have the torque converter mount bolt holes that the Camaro transmission needs. Of those two, the lace of torque converter mount bolt holes is the easier (and probably cheaper) to solve - large flexplates are available with the proper holes.

Other than that, like duckman said, they will swap.