That's why it's a theory.
They came out with the roller lifter, no squrt hole, thinner rings, and less zinc, - all bout the same time.
So it's a proces of elimination .
They started using roller lifter because they KNEW they were changing the oil. The squirt hole does nothing because the oil leaving the rod bearing around its diameter is much more than what the squirt hole does.
The BBC is a cam eater because the cam tunnel is much more closed off than most any other V8. I never saw many cam failures until the Clinton years when Romney capitalism came to the fore and made leverage buyouts the soup of the day.
Failures today are largely break in issues or worn out blocks or bad machining. Plus, today’s choice of FT lobes are much more aggressive than the were even in the early 1990’s.
