273-318 rocker shaft differences
If it were me I would op for the new hardened shafts,as the adjustable rockers use a harder shaft than that of a hyd. cam shaft of the 318. Also it's money well spent as the new shafts will help to stop the flexing of the rockers and valve train and making the engine not operate properly. As we know Mopars have problems with this from the factory it's a inhearent problem.
BJR Racing