The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1973 - 1987 Chevrolet & GMC Squarebody Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 07-18-2009, 09:47 AM   #1
dga93
newbie
 
dga93's Avatar
 
Join Date: Feb 2009
Location: Wise Virginia
Posts: 122
New Problem

When i got my 78 truck i was told they changed the whole drive train.
motor transmission and rear end. and then b4 they sold it they put the original motor and transmission back.
I found out yesterday while following my friend home that my speedo is way off.
We were going 55mph but on my speedo it was showing 65mph.
Is there something i can do to fix this problem? could it be the tires? The wheels are 17 inch with 275/60/17.

Last edited by dga93; 07-18-2009 at 09:49 AM.
dga93 is offline   Reply With Quote
Old 07-19-2009, 02:29 AM   #2
78 Big10 454
78 Big10 454
 
78 Big10 454's Avatar
 
Join Date: Jul 2008
Location: Pismo Beach, CA
Posts: 838
Re: New Problem

Odds are it is the wheels. My '78 came from the factory with L78R15 (235R15) tires. Everytime I've swapped out wheels on it, I had to take it to my local speedo shop and have new gears installed so the speedo is somewhat accurate.
78 Big10 454 is offline   Reply With Quote
Old 07-19-2009, 02:54 PM   #3
Eyegore
What Hump?
 
Eyegore's Avatar
 
Join Date: Apr 2003
Location: New River AZ
Posts: 2,009
Re: New Problem

Do you have a speed odometer shop in your area? All you have to do is detrmine the correct ratio and install the correct gear. It's just on the side where the odometer cable goes into the transmission, pull of the little braket after disconnecting the cable and pull the gear out.
It's been a long long time since I've done it.
Tom
__________________
Lil red 86 c-10
99 Sub
78 Camper Special w/ 454
Eyegore is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 04:00 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com