Hmmmmm.... Having driven a dump truck, the Chevelle wasn't that bad but cornering was biggest difference. Decent suspensions for corners and weight distribution was something only race cars had back then and they still weren't as good as todays.
The 1275 reaches 200 degrees F. That may be a touch light for hardened grease. You might want to spray the engine bay with a degreaser first and let it sit for a bit. Then the steam cleaner should work just fine.