318 build up
I have, in my collection, several sets of well used SBM rods, from the late 60s to mid 70s. Some are 318, some are early 340, and some are early 360. All have the same casting numbers. Some are bushed. Some are for pressed pins. I have not weighed any of them.
The point is, I like the full floating ones, mostly cause I can take them apart at home.They definitely appear more robust than the 273/early teener rods.