There can't have been that many cars with a de Dion rear axle on leaf springs. Then there's disc brakes all round, and a V8 engine that looks to have belt-driven camshafts.
Given that there's an obscure relation to the Maserati Quattroporte, I think this might be the Glas 2600 V8 Coupe (1965-67). Glas were pioneers of belt-driven camshafts, and the V8 had bodywork by Frua, who also designed the original Quattroporte. I think the 2600 Coupe was known as the "Glaserati" because of the similarity in the styling.