Thanks, I couldn't remember about 66 (and the only 66 Barracuda I've ever owned was a slant six). My 67 was originally a slant six, too, so the ones I had on my 360 it for a while were not the original ones. (In case you're wondering, one valve cover cracked around one of the valve cover bolts. I still have them, might try fixing that one day and putting them back on something.)