Sea foam is great! my machinist recommended it after I complained of top end noise in my 2007 patriot. Apparently it had sticky valves, and was a little pokey. I put a full bottle in the tank, and drove 15 miles home. By the time I got home The noise was gone, throttle response improved greatly, and the new buyer was tickled. my 66 Polara had been sitting for an extended period, and I could hear lifter noise. I changed the oil and added a bottle as well. After about 25 miles the 383 really perked up, and the lifter noise disappeared. To this day the 383 hasn't done it again, so I recommend it.