318 connecting rods

Definitely so. If the 340/360 style rod is any lighter than the stock rod, it would be because they were able to reduce the amount of material in the body of the rod with the selection of the higher strength alloy. I’m going to use a set of 273/318 bushed rods in an upcoming project. Coincidentally, my machine shop operator claims that for 90% of the street builds, the stock Chrysler rod bolts are more than adequate. Chrysler learned quite a few things about aerospace grade fastener materials over in their missile and space division. Grade 10 fastener markings are commonplace on oil pump and cam retainer bolts.