This is 1 1984, which I believe already has the double row timing chain. I've driven 560's, and yes I could see the take-off was a bit slower. However, I drive mostly highway to work, and I'm not a jack-rabbit starting kind of guy. 0-60 diffeence from 380 to 560 is notable, though (11.5 to 7.5), and the point is weel taken. I has started looking at 560's with 65 or 75k on them, but asking price was around $22,000 on the ones around here. Abit steep for a working guy like me!