Unable to remove heat stove from ram's horn

[AlmostClueless]

Hi, everyone,

New to this forum, so hope I'm posting to the right place. My wife and I just purchased a very, very rough 1972 4x4 Suburban w/ the 350. It's been sitting for about 30 years outside and needs a lot of work, but right now just trying to figure why engine is locked. Hoping just relatively minor rust in the bores, but need to pull heads. This is where I need your help. I removed all the screws I could find that hold the heat stove on the driver's side ram's horn, but while it's loose now, it still won't separate completely from the manifold. Obviously, I missed a fastener someplace. Can anyone steer me in the right direction? I can't get to the center 2 manifold bolts till I get the heat stove off & so I still can't get the head off. Thanks for any input & take care.