1937 21 stud engine info

[Brian]

those holes are present in all Canadian engines with liner main bearings, ie 36 LB on.... Quick and easy way to identify LB 36 engines. American engines didn't have that feature. There is another of those holes at rear of those blocks, can't see it with the oil pan on. I assume they were drilled during manufacture to be used to locate the blocks in fixtures for machining.