Rear end ratio? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**The Rocknrod** · 12-30-2019, 12:10 PM

Here is the chart on rear axle codes. The stamp is on the top of the drivers side axle:

**Steeveedee** · 12-30-2019, 12:32 PM

If it's original, per the Rod's chart it's a 4.57 ratio. A 700R4 trans has a .7 ratio OD, so that would give you a 3.2 ratio in OD. That's a respectable drop in RPM! The 700 has a really steep first gear with a big drop in RPM from 1st to 2nd. A lot of people use a 200 for this reason. I think that I recall that a 200 needs a bit of beefing up if it's going to be used hard, though.

**OL SKOOL** · 12-30-2019, 12:39 PM

Quote:

Originally Posted by Steeveedee

If it's original, per the Rod's chart it's a 4.57 ratio. A 700R4 trans has a .7 ratio OD, so that would give you a 3.2 ratio in OD. That's a respectable drop in RPM! The 700 has a really steep first gear with a big drop in RPM from 1st to 2nd. A lot of people use a 200 for this reason. I think that I recall that a 200 needs a bit of beefing up if it's going to be used hard, though.

I also have a 200r but I want to kind of use this truck for hauling a car and trailer once in a while. I didn't know if the 200r would get it done without dumping a bunch of money in it. Most of the use will just be driving around. Thank you Mr.Steve.

**OL SKOOL** · 12-30-2019, 12:33 PM

Thank you Rocknrod looks like they were all 457 ratio. Probably not too good to cruise around in even with a 700r. So probably a rear end change, so it will be more user friendly. Just trying to figure out what I will all need before I go look at this truck.

12-30-2019, 12:10 PM	#1
The Rocknrod Moderator Join Date: Aug 2011 Location: China Spring, TX Posts: 7,280	Re: Rear end ratio? Here is the chart on rear axle codes. The stamp is on the top of the drivers side axle: __________________ Master Chief, US Navy, Retired 1964 C10 Step-side Short Bed - In Progress 2009 2500HD Duramax LTZ 1948 GMC Panel 1956 Big Window Stepside 1953 5 Window Chevy Stepside 1932 Coupe New Seat Foam for Bench Seats?

12-30-2019, 12:32 PM	#2
Steeveedee Who Changed This? Join Date: Jan 2013 Location: Simi Valley, CA Posts: 10,974	Re: Rear end ratio? If it's original, per the Rod's chart it's a 4.57 ratio. A 700R4 trans has a .7 ratio OD, so that would give you a 3.2 ratio in OD. That's a respectable drop in RPM! The 700 has a really steep first gear with a big drop in RPM from 1st to 2nd. A lot of people use a 200 for this reason. I think that I recall that a 200 needs a bit of beefing up if it's going to be used hard, though. __________________ ~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA

12-30-2019, 12:33 PM	#4
OL SKOOL Senior Member Join Date: Feb 2010 Location: rochelle il. Posts: 357	Re: Rear end ratio? Thank you Rocknrod looks like they were all 457 ratio. Probably not too good to cruise around in even with a 700r. So probably a rear end change, so it will be more user friendly. Just trying to figure out what I will all need before I go look at this truck.



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.