If you knew what you were talking about, or do some research, you would find there was indeed a period of pinto engine failures due to a deletion of an oil passage to the valve train. This was a known shortcoming. and as for a 400 SBC I used to replace those junk engines around 50K - 60K because on the street the bores would go oval and cook rings from the uneven cooling. These were factory engines. No one had touched them. They might be fine in a race car that runs 18 seconds max, but a street car idling with steam holes for cooling between cylinders, what a stupid design!!! In the 70's you would be lucky to have any SBC run 100K. They would only make 70K in a pickup due to timing chain failure. I had so many 4 bolt main high nickel blocks with forged cranks, I would give them away.