The one I posted has sold. That chassis manual covers all series that year. There is no Riviera specific one. You can even get them on a CD ROM. http://www.gearheadcafe.com/servlet/the-507/1965-Buick-shop-manual,repair/Detail
Larry... it's gone because I bought it! Got the body manual too. Both for less than $50 shipped. Figured as long as I was spending money....might as well.
When I purchased my '72 GS, the first thing I dis was to go on the hunt for the chassis and Fisher body manuals. The first time u reference these manuals, they have paid for themselves!!
