1970 3963512 Block Strange One

[3macs1]

Just thought I should share this info. Had a call last night from a good friend who has been working in an engine shop rebuilding motors for over 40 years. BBC his speciality.I told him what happpened with my 512 block.
He indicated that he has seen that many times over the years in the 70-454 and in 66- 396 and 427's . Most of the oval port 4 bolt's did and some didnot not have the oil filter bosses drilled for external oil cooling and dropping the pan was the only sure way to know what you have. He said if you don't beleive me colvin ????mentions it also in his book. They would fit the caps due to potential warranty issues but machining for an oil cooler was not necessary to complete the vehicle.
Sure enough I checked today and on page 57 a note is listed
In many cases, due to scheduling and parts availability, a 4 bolt block was used in a 2 bolt application.
Also stated many times during a block production run, a 2 bolt block might have been drilled for a 4 bolt application with no factory documentation of the change"
To sum it up best to drop the pan before we sell a BBC especially if it is a 66 or 70.