Even on GTA Source Page (which is an awesome resource), I was still missing some codes. Found this site - VERY helpful and complete!

Only one I cannot figure is 1SZ, which is a trim level, I believe.

Anyways, here's the site:
http://jameshalderman.com/images/RPO_Codes.pdf

Hope this helps

 

Plenty of those definitions are year, or make/model specific. The same codes I can never find definitions for, aren't in that list either.

 

Ye8 page 58...Engineering test car!

 

Right, but others are broader in stroke. I found all but one, and was "missing" about 8 from earlier. Hopefully it's helpful. I haven't seen anything which defines all, outside of GM.

The GTA Source Page is pretty cool, too. It's list shares production of the option on GTAs, which is neat.

Here's that link for 1989 cars (others at site) for those who might not have seen it:
http://www.gtasourcepage.com/89RPOFigures.html

 

It has the same issue as generic sites because RPO codes get recycled by GM.

Our own ThirdGens has a good example of this. Just look at RPO code Y84:
Y84 MERCHANDISED PKG, GTA, TRANS AM

But before it was the GTA, it was the Special Edition Trans Am in 1982-1984.

 

My car also listed RPO 1SZ. It was described on the invoice I obtained from Pontiac as "Option Package Savings" and shows as a reduction of the overall cost of the vehicle. It was a discount offered if you purchased the 1SC Option Package containing power door locks, power windows, body side moldings, power mirrors, and cruise control.

 

Thank you, Tavert91

 

Nice find!

For 1SZ my source shows (and I don't know what it all means):

OptControlNumber
35666

OptType
P

OptNounName
DISCOUNT

OptDesc
OPTION PACKAGE

ActionDate
890410

OptionID
P

RequestingDivision
1

OwnerDiv
E

ActivityStatus
A

VPPS2
00.00.00.00.00.00.00.00.00

CompL3Vpps2CodeWithoutZeros
0

VPPSDescLower
Vehicle