I was wondering if I could swap the 85 mph speedo with one that registers higher. If so which ones work and how do you do the swap? I have an 86 z28. would I have to change out the speedo cable also?

 

i believe the speedo itself is calibrated internally so it should work fine with the cable you have

 

Just wondering, are you racing the car to need to register that speed?
And don't forget, it's a lot easier to "peg the needle" on the 85 mph, but a higher one won't make the car go faster!

 

welllll at some point very soon I am stripping the car down to the body and building it up from scratch. restoring and replacing everything I can with new parts, and drag racing in mind. I really want to put it on the track when I am done. but that is looking to be a 2 year project for me. I am reasearching to see if I put the money into it if I can get at least 600 hp out of my motor if I build it from the ground up, ( should be semi easy considering it is a new crate motor.) but I am going to wait until I actually start that project before asking those questions.

the reason I want to change the speedo now is that I was racing my friend and his car shuts down at 125, so we were guessing I was going about 130+ and I just would like to know how fast my car really is going so I dont have to guess.

 

I'm pretty sure a cop will be nice enough to tell you how fast you're going when he nails your car!

 

yeah I know. its not like I do it all the time though, besides it was an empty highway and I know both the cops in the town and could probably talk them into racing me as well. it is a tiny town with a long straight 4 lane highway. Talking Mayberry here. Right or wrong I still want to replace that speedo

 

i swapped mine for a 115 speedo just because the 85 just didnt look right to me. wasnt proportionate in my opinion. all you need to replace it is the speedo from a camaro 82-90 that has the 115 speedo. i think thats the fastest one in camaros. might be wrong

 

I had thought the later Irocs had a 145 but I might be thinking of 4th gen. Or could just be completely wrong all together. I was hoping I wouldnt have to replace the speedo cable and all. I will try looking for a 115 this weeked. Thanks alot for the info.

 

i may be wrong about the 115 being the fastest. i would just look around the yards and see what you find. as long as its 89 or older you'll be good. i think i said 90 before. i was wrong if i did

 

1989 irocs have 145 i know for a fact as my neighbor has an 89 iroc with the 145 all stock in mint condition.
i want the 145 too as ive past 115 easily and want to know how fast im going when i hit the odometer reset switch