If money is the object then go with a crate motor and get a warranty and less sweat equity. If the original 283 is a must, then just run some early power pack heads or rebuild the old heads. Your HP gain is going to really come if you want to spend a lot of money. Keep the carb between 400 and 550 CFM with a RV cam and some good valve springs. Put on a dual port manifold and an HEI ignition. You will get a good low end torque motor that will run for a long time. Don't let some parts house jockey talk you into a bigger carb or a high output oil pump. You will loose the bottom end torque with to big of carb and the stock volume oil pump is just fine. A bolt-on new carb would be the 570 Holley Avenger series. A little big, but it will work.
If you want to build a good HP motor, start with a 350 and spend some money. I wouldn't waste too much money on a 283 if HP is your game. If you stick with the 283, keep it a mild street driver and save your money.
