New pistons in 68 318

iirc 273 pins are extremely heavy due to the thick wall thickness as they were deliberately made that way for the purpose of not haveing to rebalance the 273 rotating assy with the crank it used (I'm sure I am missing some info on that) but you might be able to use them to restore the reciprocating (pistons/rings/rod small end/locks (if used) weight gram amt to what it was. when you press off the old pistons then clean one & its rings & HF has a cheap digital gram scale for $9.95 & it is just as accurate as my now deceased buddys' high dollar one. compare this to a new piston/273 pin & you can drill out the 273 pin ID (thats where the extra weight is) till the weight matches. this'll save you from rebalancing. it sounds harder than it is tho the redrilling would take some time. Holler how it turns out.