Hello to all! I have an 86 camaro sport coupe that it is all stock except for the 3.4L I swapped in it. Never could have done it without this forum and ked85. Anyway, I have stock 3.42 gears, and an 85 mph speedo. I have picked up cheap a 115mph unit.

Do I have to change the driven and/or drive gears or can I just bolt it in?

If I get the 145mph speedo, is it a bolt in?

I am trying to avoid removing the tailshaft at this time. Also, I have searched this site in the transmission section but could not find a direct, complete answer.

My camaro was the first chevy i have ever owned and it is the first GM car I have owned since 1989. I love it.

Thanks
Rick

 

I'll throw this out to ya.
I've got the same problem.
I have speedo heads for a 160 MPH readings.
What I plan on doing is just leaving what I have alone.
WHAT YA CAN DO IS!!!
IF ya have a tach observe what the RPMs are to the speedo reading of the original speedo.
NEXT insert the 115 MPH & see what happens.
WHAT MAY BITE YA IS
the 1986 set up is "not cable driven" speedo
I hear the words electric speedometer being thrown around often.
REALLY PLEASED YOU ARE STILL PLEASED
Keep at it for every detail to make it a better car!

 

the '86 I believe DID use a cable, and the 145 uses a cable too. You will have to change your speedometer gear in order to make it work properly. I have an electric, so I have not had the pleasure of this task. I believe the gear can be removed from the cover, but it may require removal of the tailshaft.