Replacement 2.8's

Hi all. A friend is getting into 4WD's after I loaned him my old Blazer for a few days. He went and bought a 87 with a blown 2.8 that is in beautiful shape for $600. He needs to keep this cheap per an agreement with his wife.

So can anyone tell me if any 2.8 will work or does it have to come from another Blazer\Jimmy or light pick up? Also, how close does he have to stick to as far as the year of the 2.8? I couldnt find anything on these 2 questions with a search.

Thanks

Dave