I'm assuming this is for the track. In a later part of the post you used the term cafe racer which to me isn't a track bike.
Are you an experienced racer? If not, build the engine incrementally in the off year. I think, if you are a beginner, there is a lot more in the bike than in the engine. If the engine is healthy go to pods or stacks and re-jet, advance your timing, cut off the stator end of the crank and run a total loss system. (I'm saying that because I don't know of vintage races that are endurance so you don't need the charging system) If you are shifting at stock red-line the stock points system is adequate as are the coils. It isn't difficult to drop in the 650 cam so I'm told. I'm doing that this off season.
Everything on the bike is heavy. The wheels are expensive to change but 7 pounds = one horse power. Go to dual brakes with a master cylinder from a later CBR, you'll stop very well. You don't have enough horse power in the engine unless heavily modified to spin your rear wheel but you need a very good front tire. Learn to use your weight to brake, turn and accelerate. Gear the bike for the track you're on. That is easily done with rear sprockets but you need a chain for each different sprocket. Get your forks set and working as well as you can.
In summary I'd say that unless you are experienced and reasonably good you need to have a reliable bike and you need to learn to race. A lot of engine isn't important at the beginning stages. You need to race and as you get better you make the improvements to the bike that you can use.
