6 to 350 Swap: Will stock 67-72 Ram Horn exhaust manifolds fit an 80's 350?

[Davids71C20]

I'm swapping my 6 for a 350 and I'm wondering if the 67-72 Ram horns a got will fit a GM Crate motor #10066036. I pulled it from a 1981 C10. I skimmed over something on here just mentioning that they don't fit but they didn't elaborate so I'm looking for more info. I know I'll probably need to change the dipstick to the driver's side which is going to be tough since its already in the truck with the oil pan on and I have no idea how to get the stick filler rod or whatever that thing is out or what I'm going to plug the other side up with.

My big thing is the manifolds because I'm on a tight budget and I've already spent a lot of money on this swap so if this doesn't work, then I might just rebuild the 250 and sell the 350 67-72 stuff.

I appreciate you input. Thank you.