318 just started knocking???

Haven't run it until warm yet. Not much water came out, maybe a tablespoon or two, but it only ran for a few minutes. Oil looks good, but have been burning it up lately. I'm putting a quart in every 50-100 miles. Replaced valve cover gaskets months ago to stop small leak but still leak small amount after driven from rear of motor. Will check plugs tonight and perform radiator test. This is all new stuff, as this car has been very strong before this.