4.7 engines can avoid most overheating issues with radiator cleaning or replacement at 90-100K, thermostat replacement, and antifreeze replacement.

Once the headgasket is violated, any goo you put in there won't seal it, rather just cause more issues, which you already figured out.

 

Sounds like the same thing I went through last year. After replacing my thermostat, water pump, radiator, blah blah... still had a heat issue. Had to replace my fan clutch. Problem solved (for me).

 

how hard is it to put headgaskets on a 03 dakota 4.7 v8?

 

You have to tear the whole top of the engine off. Not a job for someone with no real rebuilding experience.