The windage tray was broken on the last 2 of my Buicks that I took apart. I thought one of the cars had a rod knocking but it turned out that the windage tray had broken at 2 of the mounting points and was flopping around. Oldschool85 might have more of them: Buick 455 Windage Tray | V8buick.com
How did you make out? I have one for free...you pay shipping. PM me if interested with address details.