Casting # vs part # C-1, C-2 era

[Verne Frantz]

I was wondering if anyone has any theories or practical understanding of how or why the relationships between casting numbers and part numbers exist the way they do. Many part numbers are off by one digit from the casting number, yet many other casting numbers have to relationship to the part number.
I'd like to gain a better understanding of how the "process" took place. Looking forward to everyone's thoughts.
Thanks
Verne

[Verne Frantz]

Meant to say "have NO relationship" *NM*

[John H.]

Re: Casting # vs part # C-1, C-2 era

Verne -

All cast parts began life as a casting number, which was the drawing from which the foundry patterns and cores were developed and indicated the machining required for the base usage of the finished casting; in this instance, the casting number and PART number could be the same number. As additional usages were developed that used the same casting but had finish machining differences, each of those usages were assigned a different finished end item PART number. The same basic casting number could end up as many different finished PART numbers, depending on unique finish machining operations required for different vehicle applications.

[Verne Frantz]

Re: Casting # vs part # C-1, C-2 era

Thanks John,
I was primarily wondering about the many cast parts that have had only one part number assigned to them, and if there was some sort of protocol or sequence of number assignment to explain why some parts share the same casting number and part number; some are 1 digit off and some are completely different. If Chevy used a "system" of number assignment, it wasn't a simple one. (at least I can't figure it out). Just one more thing I probably don't need to worry about....

Verne

[John H.]

Re: Casting # vs part # C-1, C-2 era

Verne -

Art Armstrong can tell you everything you never wanted to know about how the part number assignment system worked at Chevrolet and how they dealt with it in the drafting rooms. He's doing a color tour in the Upper Peninsula in his motor home this week, and probably won't be on-line for a week or so.

[Verne Frantz]

Thank you sir

If I see him posting, I'll try to direct his attention to this thread....