87 cylinders are 5 studs and so is the head and the 88-90 has a 6 stud cylinder & head so 87 cylinders ONLY work with 87 heads.

If you have an 88 cylinder you can use a 88, 89, 90 head on it as they are all the same.


I would recommend here or ebay for a 88, 89, or 90 head to match your 88 Cylinder.


Its not a 500, a 250.   87-92 250 all have 6 head studs.
 
    The shape of the dome is different between the 87 250 heads I have  and the 88-92 heads I have.??