I have been seriously considering upgrading my Dana 60 with 4.88 gears to something I can get 60 mph out of. I have a strong desire to travel to Truckstock and other locations that 48 mph just makes difficult.

Since I don't have welding skills, I want to find a direct bolt in. My carrier will only go to 4.10 and that won't get me the speed I'm looking for. I think a Dana 60 with 3.73 should get me.

I have heard that 57-72 8 bolt Dana 60 is a direct fit, but I have also heard that 68-72 is the only direct fit. So, before I spend money for the wrong part, what should I be looking for?

I need to keep it 8 bolt lugs, and would prefer to stay with a Dana 60. I'm a stocker, but I also have the farmer mentality of making what you have on hand work to get the job done. The path to the darkside is a slippery slope, I must avoid the cookies.

 

F250 Dana 60: 3.54 introduced in 1966 .. 3.73 introduced in 1967.

 

Thanks Bill.
Do you know what ratios were available in 55?
Are they all the same width? I guess spring perch would be an issue too, but I assume I can have someone move those easily.

I wonder if 3.54 would be too high, but I currently have zero use for first gear on my t-98.

 

4.56 & 4.88 / From what I've read here, 1955/72 is supposed to be a direct swap.

 

Joe, whatever happened to the one you wanted to go look at?
We could probably change it in a weekend. You’ll need to get a new gear for your speedo cable so your speedometer will read right.

 

The guy just disappeared. The the ad was gone. I can only guess that he sold it to someone else. Yep, speedo gear won't be a big deal. My dad had a 54 Chevy that he just had to know what 55 was on the gauge. Not sure how he did that back then. But today it is easy with our phones.

Yes, it should be an easy change. Cleaning up the new one will be the biggest chore. Well, after I find one.

 

Let me know if you need some help.

 

I would love to have you help. Hopefully I can find one before long.

 

I have an ulterior motive: Flatlanders Truckfest 2018.

 

Joe, you've got to be able to go faster than 48mph. I have 5.83 in my f350 and I go 60mph. I think maybe you are taking it too easy. What do you guys think? Or am I getting too many rpms on my truck at 60mph?

 

That's a good question. I don't have a tach so I'm not sure of my rpm's. I think Ross had said the Y-block can run at 3000 rpm forever. I'm probably babying it a bit.

I went to here to check values: RPM/MPH From Gear Ratio Calculator by Wallace Racing

With my 31" tires and 1 to 1 transmission ratio in 4th. I get this:


So by this, my ear seems to think about 2500 rpms are comfortable. I need to break down and buy that 6v tach. Westach sells them.

How tall are your tires? Do you have overdrive?

 

Now, this gets me thinking. What else is involved. I have gotten my truck up to just above 70. It was downhill and I had it floored.....Oh, my carb will only push so much fuel?

 

Hard way or easy way ? Just slide a midship auxillary with OD- Direct and under. Little
drive shaft work you will be glad you did. They are out there just gotta look for them. Prime
example my main trans has overdrive my and my auxillary has overdrive. About oh
around 50mph put main in od. run her up to about 2800 rpm put aux in OD; now just
too fast for old bones and eyes..... lol : America ya just gotta slow down "55 saves fuel and
lives" What you don't know is it takes about 20min for us to dig your vault an lower you in.

 

I do not have overdrive. I did figure out the approximate rpms at 55mph, 60mph and 65mph but it is written on a 3x5 card in my glove box and I'm not home now. I'll report back tonight.

I think at 60mph it was 3500rpms..... not positive, though. In my 6 hour trip on Tuesday it did not over heat at all.

 

You want to go FAST! Sounds like a Mid Life crisis to me Joe? I'm just looking forward to to any speed! That's what happens after sitting in pieces over the last year. Wish I could help you reach your goal. Good luck with your venture!