The following are links to PDF files
Kohler 18HP and 25HP Maintenance Sheet
Kohler 18HP and 25HP Performance Curves
Kohler 18HP and 25HP Emissions Data
GM 3.0 Liter 4-Cylinder Brochure
GM 4.3 Liter V-6 Cylinder Brochure
GM 5.7 Liter V-8 Cylinder Brochure
GM 8.1 Liter V-8 Cylinder Brochure