This will probably work out to a monster---
Garry--It all comes down to how the
oil feeds thru the crank to get to the rod bearing--
With a half groove main(top half) the
oil has a route to the rod for 180* rotation of the crank. Then years ago , someone made grooves in the main journals of the cranks so they would
oil 360*. Then someone crossdrilled the main journals so that one or the other holes were always exposed to oil---then the engineers fiqured out that dividing the main surface into two halves actually lowered the capacity of the oil film to only about 1/4 of what it was---now, they don't cross drill mains anymore but since all the load on the mains is in the lower quarter, they have made 3/4 groove bearings which supply the rods much better than half grooves but doesn't lose the oil film load ability of the lower main---????????