[Keith Seymore]

Excellent chart, John, and it helps show what I was trying to convey.

You can see there are several engines listed for RPO LS9, a 350 cu in V8 (what they show as the "VIN" column). Within that RPO you have to have different part numbers for Federal emissions, California emissions, manual trans, auto trans, maybe even A/C vs non A/C, or even different product lines (ie, a C/K engine might have a different part number than a G van engine).

Rather than have the operator scan through all the different part numbers, he is told to simply choose a TBC (rather than a TBD, TBE, etc).

Axles are another good example, because even though they might have the same RPO for the ratio (ie, GT4), they might still vary by C vs K (number of lugs), brake RPO and posi vs non. Various part numbers and subsequent broadcast codes would be assigned so the guy selecting the rear axle can quickly chose the correct one and hang it on the line.

Same thing for radiators (A/C vs non A/C, manual vs auto trans, HD vs LD vs standard duty, etc).

Incidently (this is really super picky), it appears to me the column that they show as "RPO" is really incorrectly labeled, and should be labeled either "Broadcast code" or "suffix code". I recognize the LS9, LG4 and L69 codes as engine RPOs that we used to work with. Other codes you might see might be LB4, L18, LE8, L03, LO5, etc, for example.

HTH -

K