Hello everyone,

I have just opened the engine of my 1959 Oldsmobile Dynamic 88 371 cubic inch motor for rebuild, I was measuring the clearances and was looking for any stamp on the tang, the main bearings 1-4 had a mark B and the main bearing 5 had A, what is A ??. Because I don't see anything mentioned in the manual about "A"

There is no mark on the Connecting rod bearing should I assume as standard size?

Any help would be appreciated

Thanking you

Samanyu