well i got everything put together,(new piston rings, intake and exhaust valves, head gasket, intake and exhaust gaskets, distributor gasket, spark plugs and wires, cap and rotor) and everything runs great and smooth BUT!!! at low RPMs(1000 to 1500) and when you let off the gas there is a loud rattle, it kinda sounds like it is miss fireing i think(but im no mechanic). Any thoughts on what it could be i have tried everything i can think of, including messing with the timing but it runs so smooth at a high idle that i dont want to mess with it to much. Every once in a while it will make that rattle sound just once then go back to running smooth at the high idle(1500 to 2500)