sae vs metric

[tdm571]

Pretty much everything on a 3800 is metric besides the valve cover bolts.

That's not been my experience. Yeah, you could use a 13mm on some bolts, but there is a little play and a 1/2" fits perfectly. Like the dog bones or the fender braces. I don't remember off the top of my head, but I know there were some SAE bolts when I taking the heads off in the junkyard for a top swap. I think they were 7/16.