Allan

I've seen IROC-Z's with 85MPH speedos .. only in 1985 ...

When did IROCs come with 115 speedo's ... when did they come with 145 speedo's? I'm thinking TPI engines = 145 speedo? could be wrong ... very wrong!

Square shifter **** versus rounded. Some have said that the square ***** came with 350's and the rounds with 305's, but I don't think that's the case. I'm thinking 85 was rounded, but 86 up was square ... or was this ALSO induction based (TPI vs. TBI/Carb) ...

Last ?. 5000 redline vs. 5500 redline. When did IROCs have 5500 redline tachs and when did they have 5000 redline tachs?

Remember, I'm talking strictly IROCs here.

Willie

iTrader: (1)

I've seen IROC-Z's with 85MPH speedos .. only in 1985 ...When did IROCs come with 115 speedo's ... when did they come with 145 speedo's? I'm thinking TPI engines = 145 speedo? could be wrong ... very wrong!

First off, the three years, 1985 - 1987 when the IROC-Z was an option on the Z28, the following information applies to both:

1985 Z28/IROC-Z
85-mph speedo (all cases)

1986 Z28/IROC-Z
85-mph speedo (all cases), however the 145-mph speedo was introduced late in the model year run on 305 TPI equipped cars.

1987 Z28/IROC-Z
85-mph speedo (LG4)
145-mph speedo (LB9/L98)*
*Including convertibles with LB9.

1988 IROC-Z
115-mph speedo replaced the 85-mph speedo (L03)
145-mph speedo (LB9/L98)*
*Including convertibles with LB9.

1989 IROC-Z
115-mph speedo (L03)
145-mph speedo (LB9/L98)*
*115-mph speedo for convertibles.

1990 IROC-Z
145-mph speedo (LB9/L98)*
*115-mph speedo for convertibles.

1991 - 1992 Z28
145-mph speedo (LB9/L98)*
*115-mph speedo for convertibles.

I'm a little hazy on the convertibles from 1989 thru 1992, so please correct me if I'm incorrect.

Square shifter **** versus rounded. Some have said that the square ***** came with 350's and the rounds with 305's, but I don't think that's the case. I'm thinking 85 was rounded, but 86 up was square ... or was this ALSO induction based (TPI vs. TBI/Carb) ...

This is misinformation that's floating out there. 1986 was the last year for the round automatic shifter ****. It was replaced in 1987 with the square ****. Remember, we're talking automatics here. And there is one exception. The 1984 - 1986 Berlinetta got the square ****.

Last ?. 5000 redline vs. 5500 redline. When did IROCs have 5500 redline tachs and when did they have 5000 redline tachs?

Tach Redlines:

1985 Z28/IROC-Z
LG4: 5000
LB9: 5500

1986 Z28/IROC-Z
LG4: 5000
LB9: 5000

1987 Z28/IROC-Z
LG4: 5000
LB9: 5000 (with automatic)
LB9: 5500 (with 5-speed)
L98: 5500

1988 - 1989 IROC-Z
L03: 5000
LB9: 5000 (with automatic)
LB9: 5500 (with 5-speed)
L98: 5500

1990 IROC-Z
LB9: 5000
LB9: 5500 (with G92)
L98: 5500

1991 - 1992 Z28
LB9: 5000
LB9: 5500 (with G92)
L98: 5500

Allan

:hail: to the king. That is exactly what I needed to know! Thanks a lot Willie!!!

91z4me

Willie my 91 Z had the 115 speedo I think the 145 came with the G92 option in 91 and 92.

Willie

iTrader: (1)

Thanks for the correction. I know there are variants in the later third gen years, but didn't know specifically what they were. But all in all, the information posted above was from memory -- not bad, huh?

Willie