Lots of variables. Kinked fuel line, gas tank sock clogged, fuel filter clogged, bad fuel pump, float not set correctly on carb, to lean, too rich, timing not right, ignition issues with coil, wires, plugs not gapped correctly. Need info on initial and total mechanical timing, vac reading at idle, what type of ignition (HEI or Points, etc), what type of plugs? What type of cam is in there, what heads, and what gear ratio?What do you mean by it has no power? Does it bog, misfire, or just won't shred the tires?