I had the same problem. I attached a ground wire from the one inside the taillight housing to the frame and worked like a charm. Even cleaned up, the ground in the housing would not light my tail lights.
Go to the drivers tail light and remove the whole set up. there is a ground there that screws to the metal surounding the tail light assembly housing. Check to make sure that ground is good. Had the same problem and so ran a new ground wire and no more problem. Weird how it only effected the...
Can you peen a slight crown in the spread bar? That way it's putting down pressure on the valve cover while also putting up pressure on the bolt, there by acting like a lock washer.
There should be two brackets coming off the core support on each end of the radiator. T shroud bolts tho them. Yours appear to be missing. They look similar to the brackets holding in your radiator.