We know Oldsmobile's problem starts with the weak block webbing causing block flex. But the supposed cure is to run looser main bearing clearances.
What I'm saying is everybody has their problems and there are more that one way to skin a cat.
The crossover tube is one of the ways to save the bottom end on a hydraulic cammed sbm. It has been proven time and time agin.
I am interested in the crank timeing groove that was mentioned earlier. Also would like to see the video.