If the VIN was "S", as I noted, that meant 318 4bbl (ELE) police. That would have the 345 (J) heads.
If the VIN were 4 or R, from '85-89, then it would have 302 heads. It's that simple. The OP has since stated he has 302 heads, so he's got either a P, 4, or R in his VIN.
From '84 - '86, they...