Got a chance to make a great deal on a Suregrip

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Derek Simpson

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Hey Guys,

Ok I have a chance to scoop up a Suregrip for a great deal. The seller says it's a 1968 Dana 60 355 gears with only 20k since it was rebuilt. My question because I'm definitely new to gearing will that be ok in my 66 Newport?


Thank you for the help!
Derek
 
Derek Simpson said:
Hey Guys,

Ok I have a chance to scoop up a Suregrip for a great deal. The seller says it's a 1968 Dana 60 355 gears with only 20k since it was rebuilt. My question because I'm definitely new to gearing will that be ok in my 66 Newport?


Thank you for the help!
Derek
Click to expand...

The thing that you really need to know to start making decisions is your current ratio. An easy way to do this is to put the car on jackstands in neutral, mark your rear tire with tape on the inside where you can see it and carefully count the turns of the driveshaft required to turn the tire one full revolution. You can put a tape line on the drive shaft if it helps, I would just look at the u joint for reference. 2 3/4 turns would be a 2.73 for example.

As you go to a higher number (lower gear), you will gain low speed torque and acceleration, but at the expense of higher engine RPM's while cruising. A change from 2.73 to 3.55 would "wake up" stop light performance, but would likely suck to drive on any kind of highway trip.

I'm sure others are here who can tell you their firsthand experiences with this change in their own cars. I would be hesitant to advise someone to make a big leap without thinking it through. First step really is find out what you have and decide what you want to change based on how the car drives now.

I find in my cars that without a 4th gear, they cruise at a higher RPM than my newer vehicles and I don't really want that to get worse. I also have zero desire to do burnouts or drag race.
 
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If it is a Dana 60 you will be swapping the whole rear end and it would be a 3.54 ratio so I'm going to guess you are talking about a 8 3/4 center section. 3.55 ratio is a terrible ratio, to low for today's highway traffic and too high for the drag strip. Nothing screams fun of a old car than being in a big cruiser turning 3200 rpm and being passed by a 20 something texting in a Hyundai loafing along at 2200 rpm at 75 mph
 
If you decide you still want this rear axle then you need to get under your car and measure the length from end to end, then measure from spring perch to spring perch. Then check these measurements to the one you want to buy. You will probably need to have your driveshaft cut also. By the time you figure in all that is involved, you will probably be better off having yours rebuilt.
 
I think I just might stick with my rearend... sure it's not a sure grip but I have other things I need to get done more pressing
 
Derek Simpson said:
I think I just might stick with my rearend... sure it's not a sure grip but I have other things I need to get done more pressing
Click to expand...

SG is overrated... I prefer to be without. I would never change backward because of it, but slick roads and limited slip are a recipe for trouble. I have to expect to travel in rain where I live... and experience has shown too many otherwise good drivers can get into real trouble not realizing that if they lose traction the car will want to spin.
 
Thank you for the info. I'm just going to stick with my rearend and just do maintenance on it (show it some love) and move onto other projects on her
 
Derek Simpson said:
Thank you for the info. I'm just going to stick with my rearend and just do maintenance on it (show it some love) and move onto other projects on her
Click to expand...

I would bet the ratio you have now is likely to be a 3.23, and that is a pretty good all-around setup for a street-driven car.
 
If you have a 2.94 or a 3.23 you can always add a sure grip to a open rear dr diff sells a clutch type for around $400 plus bearings bolts and a cheap dial indicator from harbor freight, you do not have to touch the pinion which is the complicated part.
 
cantflip said:
SG is overrated... I prefer to be without. I would never change backward because of it, but slick roads and limited slip are a recipe for trouble. I have to expect to travel in rain where I live... and experience has shown too many otherwise good drivers can get into real trouble not realizing that if they lose traction the car will want to spin.
Click to expand...

Interesting . I don't do big jobs on my Fury or any car much anymore and my mechanic said the same thing when I asked about installing a suregrip. He said the car is better off without it. He was semi reluctant to the idea of 3.55 rear end too but said he would do it if I really wanted to but recommended without a SG. He said the car is new to you ,drive it ,fix stuff ,get used to it and see. I took it on the highway for the first time after I bought it and was glad the engine wasn't spinning any faster than it was at 75 mph. It has 3.23 rear with open diff. I'm not changing a thing. It is a 19 foot big block cruiser after all not a wanna be stop light racer. My opinion only. My mechanic is a drag racer. Here is his car. [engine pulled for rebuild]
20160914_104338 (1).jpg
 
Turboomni said:
Interesting . I don't do big jobs on my Fury or any car much anymore and my mechanic said the same thing when I asked about installing a suregrip. He said the car is better off without it. He was semi reluctant to the idea of 3.55 rear end too but said he would do it if I really wanted to but recommended without a SG. He said the car is new to you ,drive it ,fix stuff ,get used to it and see. I took it on the highway for the first time after I bought it and was glad the engine wasn't spinning any faster than it was at 75 mph. It has 3.23 rear with open diff. I'm not changing a thing. It is a 19 foot big block cruiser after all not a wanna be stop light racer. My opinion only. My mechanic is a drag racer. Here is his car. [engine pulled for rebuild]View attachment 109818
Click to expand...

I agree 100% about yer mechanic's sure grip comment. I'm running 3.23s in both of my '66s. Also, I really like his bubble-top '61 Impala.
 
As others have said a 3:23 is a really good overall gear, street and expressway. A buddy of mine put a 3:55 gear in his '67 barracuda and found out running at 70mph he is turning about 3000 rpm and that it now uses a LOT more gas.
My car has an open 3:23 rear that I really wish was a suregrip, you really have to feather the gas pedal when taking off from a light with any urgency. Putting it to the floor from a stop and the 440 just incinerates the tire and you get nowhere fast
 
I am going to have a ton of fun with my 3.55 sure grip 4 speed 440 wagon when I get her done. for a long trip I will stick a 3.23 in it.
 
livininharrow said:
I am going to have a ton of fun with my 3.55 sure grip 4 speed 440 wagon when I get her done. for a long trip I will stick a 3.23 in it.
Click to expand...

Always good to have a spare pumpkin with a set of cruising gears ready to go.....;) I currently have 3.23 sure-grip in the wagon, and really like it, but actually just stumbled upon a cone style sure-grip carrier section the other day in my parts stash.....no idea when I acquired it, or when....but pretty pleased about the find! Will be using a donor 2.76 or 2.94 pumpkin and setting up the 3.55 ring and pinion I have been hauling around for over 20 years, with it. :)
 
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