Dunno, but I will never, ever, ever buy any Manley part again. They made a bum set of pushrod guides for my 1966 Chevy big block that caused two dumped exhaust valves. On a practically unreplaceable original block and heads. Took some detective work to find the problem, too. If they can't make dumb iron like pushrod guides, I'm sure not gonna risk a motor on their valves.