cylinder head casting numbers

I found these numbers on my cylinder head under the valve cover 2843670-24.....okay I checked the numbers and it says they came from a 318 BUT it has aawj on one runner also (are they j heads).....I KNOW I took them off a 1975 360 block but the numbers are saying 318 cylinder head but from what I read/heard that j heads only came on 340/360.....Could someone help me out? Thanks......