1972 - 4 bolt crank shaft bearing caps

[Jerome P.]

The numbers on the bottom of each of the 4-bolt bearing caps each have the number "2482" on them. However, a second series of numbers/characters each cap is different i.e., GM 24 NF, GM 18 NF, and GM 20 NF. Does any one know what these number represent? I do not believe they are part numbers. I think the part number is 3956686.

A second question is were is the part number located on these bearing caps?

Thanks

Jerry

[Terry M.]

Re: 1972 - 4 bolt crank shaft bearing caps

The numerals GM 20, GM 18 and so on, are the mold numbers in which the part was cast. You will see similar alpha-numeric characters on the cylinder case, heads, water pump, iron intake manifold, and many other cast iron parts. I think the N in NF is for nodular, a type of iron. The F is for the name of the foundry that cast the part, but in this case I don't know what F is. D = Danville Illinois. Here are many others that I don't remember, but Joe Lucia has all those locations snd the type of iron they poured right on his mind.

As far as I know there are no part numbers on the bearing caps. There are not usually part numbers on cast parts, however there is usually, if the part is large, enough casting numbers on cast parts. Those casting numbers are almost never the part number, and often one casting number can have several part numbers dependent on different machining operations.

[Clem Z.]

Re: 1972 - 4 bolt crank shaft bearing caps

years ago GM sold replacement nodular iron main bearing caps to replace the std cast iron ones for the 3 center caps and i believe that 3932482 was the number. they may have become std on all blocks later on