They say to set the lash 28/32 hot with iron heads I used to go 26/30 cold and that gave 24/26 hot I like a little tighter. LSA is 106 with 104 intake centerline install better at 102 or we even ran one at 99.5 then later 101. Aluminum heads lash actually opens up .004 to .006 hot and more with Indy heads.
312 duration is 265 Duration @ .050. they never cam with a cam card as far as I know. I never got one in any Mopar Performance / Direction cam I ever got.