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 1960 - 1966 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 04-17-2014, 02:50 AM   #1
Jimbo68
Registered User
 
Join Date: Mar 2014
Location: Cape Coral, FL
Posts: 3
Rear differential question!!!

I just bought a 65 chevy c10 long bed the other day, and it's got a 350 with a four speed on the floor. When I'm running 55-60 mph my engines turning around 3500rpm which I know is high but what would be a good rear gear that would help lower those rpm's and make for better cruising?
Jimbo68 is offline   Reply With Quote
Old 04-17-2014, 06:37 AM   #2
PGSigns
Senior Member
 
PGSigns's Avatar
 
Join Date: Jan 2011
Location: Hayes Va
Posts: 4,569
Re: Rear differential question!!!

For just a cruiser I would look for a 308. A taller tire helps also.
Jimmy
__________________
60 to 66 Chevy and GMC window decals
http://67-72chevytrucks.com/vboard/s...d.php?t=661131
Good friends, good food and a hotrod what else do you need?
1966 BBW long fleet Daily driver
1965 BBW short fleet Sold and going to a good home
1965 Suburban
2003 3500 Duramax
2005 Ultra Classic
PGSigns is offline   Reply With Quote
Old 04-17-2014, 06:53 AM   #3
Jimbo68
Registered User
 
Join Date: Mar 2014
Location: Cape Coral, FL
Posts: 3
Re: Rear differential question!!!

Would the 3.08 keep the rpms down where they should be with the four speed at like 60mph?
Jimbo68 is offline   Reply With Quote
Old 04-17-2014, 07:56 AM   #4
Clyde65
1965 Chevy C10, 2005 4.8L/4l60
 
Clyde65's Avatar
 
Join Date: Aug 2004
Location: DFW Texas
Posts: 8,546
Re: Rear differential question!!!

Look at this...
http://www.summitracing.com/expertad...tio-calculator

plug in your info and see what the RPM would be with 3.08's and ( I believe you have) 4.10.

Good luck. Any chance you will put an OD tranny in it?
__________________
Clyde65

Rebuild of Clyde
http://67-72chevytrucks.com/vboard/s...84#post8338184

69 Aristocrat Lo Liner build
http://67-72chevytrucks.com/vboard/s...84#post7561684



support our troops!
Clyde65 is offline   Reply With Quote
Old 04-17-2014, 08:44 AM   #5
kieth
Registered User
 
kieth's Avatar
 
Join Date: Sep 2010
Location: Tulsa, Oklahoma
Posts: 1,925
Re: Rear differential question!!!

Quote:
Originally Posted by Jimbo68 View Post
I just bought a 65 chevy c10 long bed the other day, and it's got a 350 with a four speed on the floor. When I'm running 55-60 mph my engines turning around 3500rpm which I know is high but what would be a good rear gear that would help lower those rpm's and make for better cruising?

measure the height of you rear tire from ground to top of tire, then look at the attached charts, they should tell you what you need to know...

TORQUETOGROUND_Master_r.pdf


kieth is offline   Reply With Quote
Old 04-17-2014, 01:29 PM   #6
jtrichard
Registered User
 
Join Date: Jun 2013
Location: joshua tree ca.
Posts: 1,484
Re: Rear differential question!!!

you talking a granny low 4spd? I have a 76 blazer with 307s and granny 4spd it is great down hill in a hurricane.... flat ground is not bad ...a little tricky to get rolling at first and a dog on the hills....only gets worse if you have tall tires...... I would stick in the 3.50 range
jtrichard is offline   Reply With Quote
Old 04-17-2014, 06:45 PM   #7
jdp
Registered User
 
jdp's Avatar
 
Join Date: Apr 2014
Location: San Diego, CA
Posts: 7
Re: Rear differential question!!!

Quote:
Originally Posted by Jimbo68 View Post
I just bought a 65 chevy c10 long bed the other day, and it's got a 350 with a four speed on the floor. When I'm running 55-60 mph my engines turning around 3500rpm which I know is high but what would be a good rear gear that would help lower those rpm's and make for better cruising?
I'm in nearly the exact same boat: same year, long bed, 350 sbc, 4 on the floor with granny. Putting another transmission in soon. Good luck.
jdp is offline   Reply With Quote
Old 04-17-2014, 07:44 PM   #8
Jimbo68
Registered User
 
Join Date: Mar 2014
Location: Cape Coral, FL
Posts: 3
Re: Rear differential question!!!

I mean how hard would it be to just do a tranny swap from the 4 speed to a 700r4?
Jimbo68 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 10:42 AM.


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