I have a 2004 Dodge Ram 1500 Laramie Crew/Quad cab 4 door 4wd w/5.7 Hemi. I want to put a tonneau cover on it. When looking at them they ask if it is a 5.8 or 6.5 bed. Measuring according to the instructions from inside bulkhead to inside tailgate is just over 74 inches. That isn't either of the sizes. Which size do I have? Any help is appreciated.

 

What site are you looking at?
EDIT: Since the cover sits on top of the bedrails & tailgate, I would say 6'5".

 

I was looking at Amazon at the Mostplus soft quad fold tonneau cover.

 

These trucks were offered with either 6'4" or 8' beds. You should have the 6'4" bed since you have a quad cab, and it's really rare to see the quad cabs with the longer beds.

 

This^^
Plus a QC with a long bed is NOTICEABLE.