I added an over flow bottle , just to see how much I lost ,. IF it turned hot....I bought bthe bottle from Classic (not stock for Firebirds), and moved it to the spot my windshield water bottle was, then welded the bracket for the windshield bottle to it....as this way they fit better....but had both bottles next to ea other....bracket t bracket...worked out well....and I never really lost any water, it just pushed out into the bottle , if I put too much in radiator...level should be about 1 inch below rim on filler opening........but has not "originality" look...