I have a 1979 300D with 300k+ miles. I had the intake and exhaust manifold off to install a new block heater. The intake ports were oil soaked, I know she's tired. I thought hey, I'll pull the head, do the valves and maybe throw some rings and bearings in while I'm in there... I stopped myself and thought I'd better see what this is going to cost. I can do the labor myself, so just need some parts. Well after putting together a parts list, I was looking at 2K plus machining if everything went well. SO HERE'S THE QUESTION, will I see more power in the old 300D after she has been overhauled? They weren't that gutless of the showroom floor, were they? Love the car but, is it worth the 3K...I know there are those out there that went down hard on overhauls...was it worth it?