Is it ok to fill the idler box off the car.and the steering box they where removed during the on going restoration.

Yes, that should be fine, although I wouldn't store them upside down or on their side.

-Bryan

What is the fill level for the idler, I read 3/4 below the fill plug on the steering box but can’t find anything on the idler fill level

The idler box is pretty much filled all the way up with oil, but you have to be a little careful as there are two "chambers" inside the box. The bottom one has the vanes that provide the resistance while moving through the oil, so that should be filled. The top chamber has only a small amount of oil in it. There is a separator with ball bearing one-way valves that allow oil to go from the top chamber to the bottom chamber.

If you haven't removed the top cover and the middle separator plate on your idler, this should be done is the whole thing gets gummed up over time. It can be done with the idler in the car, but you've already got yours off the car.

By the way, I'm assuming you have the hydraulic idler. Some models used a friction damper, as well as aftermarket versions, and those don't require oil.

-Bryan

Yes I disassembled completely and clean out the black gunk and replace the two o rings.I was surprised to see oil in it.