ive always been curious about the different tachs that these cars came with, i have an 89 iroc and it has a 5500 redlinebut i have seen others with 5000 redlines, is there a differnece because of the 5L and the 5.7L or is it just the cam, heads etc?

 

In 89, you got a 5000 redline tach if you had a 305 TBI (LO3) or a 305 TPI automatic (LB9). You would get the 5500 redline tach if you had a 305 TPI (LB9) with a 5 speed or a 350 TPI (L98).

 

The Tachometers matched the CAM that was installed on the engine.

In 85 the TPI had the 5500 RPM Redline:



in 86 the TPI got a cam change and the tachometer has a 5000 Redline: I think 87 was the same.


I know the crossfire engines, TBI and the LG4's all had a red at 5000 RPM. The HO engine might have been higher,............ Seems like all the 350's had the 5500 Reline but I coiuld be wrong.

 

L69 with 5 speed had a 6000 rpm redline, but it really didn't like being there. Don't know if the auto had the same.

 

That tach matching cam thing above is just a fallacy. My 86 TA has the cluster it originally came with and it had the peanut cam too, and no 5000 RPM redline anywhere to be found. I think its more 'intended' than 'absolute' just like a bunch of other things GM does.

 

I've got MUCH more experience with the Camaro's and I can't speak for all the firebirds out there, but I can say that I've parted out 4 V8 Birds.

1 was an 85 TA with a 6000 Redline. The style is very different than the 86 & up tachs.



The next 3 were from 86 & 87 Firebirds / TA's,...... one was an LG4 ( 86 ) and the other 2 (87's ) were TPI 305ci cars. ALL of them have 5000 Redline tachs.




I find it hard to believe that your car rolled off the assembly line with a ( brand new designed ) Tachometer that didn't match the RPM range of the best motors being offered in that year. Sorry - but I'm a pessimist ! I can't imagine why a manufacturer would EVER put a gauge into a car that did not match the specifications of the engine moving it.

My favorite ThirdGen ( for example ) was the digital Berlinetta. There were only 3 motors available in that platform and each of them uses a different cluster JUST BECAUSE OF the Tachometer. There's one for the LG4, 1 for the LC1 and one for the LB8. Chevy didn't just stick the LC1 cluster ( Tach ) into the LB8 cars,..... they made a new cluster JUST to match the tachometer to the engines RPM ratings.

madmaxPlease - I'm not picking a fight with you. I simply don't believe that ANY 86 left the factory with anything other than a 5000 redline tach.

L69norm Here's the Tach from an 84 Camaro HO car...... I can only assume that your L69 HO was in an 84 or 85 Firebird ????

 

Yes, mine is an 84 TransAm with L69 and 5speed.

I'm almost inclined to believe it was a marketing thing to give the owner bragging rights. While the red line was at 6000, it really didn't like it and was all pretty much all done by 5500. I always thought it felt best shifting between 4500 and 5000.

 

My cluster is date coded and matches the car, and the only other owner didnt touch it. Its original.



Here's some more info on 86 birds
https://www.thirdgen.org/forums/post...07-post15.html
Notice I have no KPH either.

 

L69Norm that idea of bragging/advertisement sounds plausible.Remember at the time the 5.0 Mustang's tach didn't have a redline.And a big reason the L69 was brought about.

And as John in RI stated the redline on my '83 LU5 Z28's tach is 5K.

 

Well - again; That's why I love this site ! Seeing that speedo and tach combo is ( yet another ) first for me !!!