What motors did Merc put these manifolds on, any idea what year range they were used?
MerCruiser Gil exhaust manifolds
Thank you in advance.

They were on a wide range of years but stopped IIRC with the HP500 around 99/2000 with the HP500efi and CMI E-Tops. Merc 420s in the late 80s I think had them first. If not it was the HP465s

Mcm 440 &460 had gil aluminums and i dont believe those were the mercruiser rebadged either .i believe those were early hp500 and bulldog . Look for seperate hose going to riser they had a few early units with cast riser going to stainless pipes, larger wet joint system

Merc 420, 525SC, 600SC, carbed HP500 and probably several others used the Merc/Gil exhaust.

HP450's also used them