I had a .450 Marlin with XS Ghost Ring sights and sold it but kept the sights. Decided to mount them on my Marlin 336 in .35 Rem but the rifle shoots too high with them. I 've got my elevation ( rear aperture ) as low as it will go.. I need either a higher front sight or will the XS sights made for the 336 Marlin be different ? The ones I mounted are for the 1895 and fit just fine only shoots too high.. Thought I would try to use them and it didn't work out as planned, so who is using the XS sights for the 366 or which brand of peep sights would be advisable ?

The folks at XS ought to be able to sell you the correct height front sight for that combination. If not a Williams or Lyman receiver sight will go much lower than the Ashley. You might even be able to keep the nice Ashley front sight. Good hunting!