383 build no power

common rookie mistake, the wrong 0 on the crank sprocket was used, so the cam is way advanced, and it will run like a dog, often the intake valves tap the pistons. unbolt the cam sprocket and rotate the crank clockwise to get the other 0 to 12 oclock. do a compression test to check for any bent valves. It will run much much better and stronger than before, and like I said the combo is not bad, just need adjusting