You will have to keep a precise account of the (stock) engine. Internals will just be new parts. You wont be making 400 HP to break anything. You can change the cam, carbs and headers. I would say get the car ready to pass smog first. Remember, YOU said you wanted to work on the car with your dad!

After you pass you will need a few parts for the engine that you can replace in a day or two. I would get extra parts just to keep all the smog legal stuff together. Another distributor for sure and a head for double springs and bigger valves

. But internals that you can change easy would be cam, lifters, push rods, carbs, manifold and maybe a clutch to be on the safe side. That would be the power with same block. If you are getting a big cam then notch the pistons. The only inconvenience that I see would be welding the ................. never mind. It will cost money but its better this way. I was going to say welding the headers on and off. But you can just keep the stock manifold, tubing and muffler. Then get headers and a muffler with new pipes. That way you can take them on and off, no extra money to spend.
What got me thinking was the 2 years part. Way better than a year. I would say about a weeks work at the most doing it part time is well worth enjoying it for 2 years.