Are these lifters compatible in a stock block?

Ugh. I wasn't aware they were dumbbell lifters. Like I said in my PM, the concern is that on the smaller base circle cams, the wide band will allow oil pressure loss. I know for a fact on a small block with a radical cam that DOES happen. I've seen it first hand and known people who've had the same issue. I'm no expert on it though so they might be ok in a big block. My early Hemi has them in it, but they are correct for those engines. I was not aware anyone even sold those for use in the modern engines. I know you can also use them on a slant six. Maybe somebody with a little more knowhow about these will chime in.