I adjusted my timng on my 400sb to where i thought it was the best.It starts right up, takes awhile to warm up, then at idle it sounds like i have a cam. Kind of a choppy sound. When i gun it, it sputters a bit then throws me in the back of my seat like it should. The engine is great at all Rpm's but idle. I want to be able to lower the idle speed so its not quite so high. The thing im worried about is if i advance it anymore, i dont want it to make the loud grinding noise when i try to start it. What do yall think i should do.. By the way, new HEI system so i know the distributor and parts arent bad.