just replaced the head on my 91 integra, w/rebuilt head (both pr4 castings) car started perfectly 1st try, i removed the valve cover for other reason later & discovered my timing belt appeared to have walked 1/2 way off the cam gears! & the gears had rubbed hard on the inner cover, upon further inspection i discovered the camshafts are a 1/4 inch shorter than the originals, so the gears are closer to the engine! does anyone know if older or newer tegs had shorter cams? help