Fleck
Fleck (60232-110) Designer Black Valve Cover For 2500;2510;2850;9000;9500
$49.50
The width is 10" at top and bottom but flanges out to 11" wide about a 1/4 of the way up from the bottom.
The height is 6 1/2". The depth is 4" at the top, 5 1/4" at the "flange", and 4 1/2" at the bottom