Does anyone know the factory 4-digit PROM code for a 1989 IROC with a TPI 305ci w/ 5-speed?

Info would be appreciated!

In '89 IROC-Z, TPI (RPO LB9) with M5 was available with two different rear end ratios (3.08 & 3.45). From my notes the following two BCC may fit your needs.

1989 IROC-Z 305, M5, A/C & 3.45 (FED) APYS 9350
1989 IROC-Z 305, M5, A/C AUJS 3509

//RF

My 1989 Formula, LB9 (305 TPI), T5, 3:45 Rear, came with ANYX. I have a virgin copy of the bin if needed.

In fact I do. PM sent.

'89 5.0TPI M5 3.08 CA = ANZA (most recent).

What does the CA stand for?

CA = the eco-**** state of Kalifornia!!! Where we can not balance budget and idiots at air resource board want to impose lower carbon fuels = $$$$ expensive.

So would the non-CA .bin be more desirable to use?

If you look through the years at HP/TQ ratings of all cars you'll find that CA certified cars had lower ratings and more emission control equipment to boot. You can thank for this a faceless, politically appointed group of people, with unchecked power - CARB aka California Air Resource Board. If you ever want to find a greater collection of technically incompentent people in the world, all in one place, it is this group of <insert fovoirite 'ist'> here. A lot of group think goes there and most of it is done in complete disconnect with reality, or its effects on people and economy in general.

//RF

Good stuff! I am keeping this string for reference. Thanks.