The way you describe it doesn't sound like valve noise. It may be too much timing. Try driving it with the vacuum line disconnected. If it doesn't chatter then it is a timing problem. Too much total advance. If thats not it it may be a little piston slap. If that is the case it will be more when the engine is cold & less after it warms up.
George
Last edited by Wrenchbender Ret.; 03/14/2021 4:15 PM.
