OK, I'm done a little searching, but I'm still not very clear.

Here is my setup: 55 F250 with T98 transmission, 4.88 gear ratio with a Spicer rear end, the ratio tag says 39/8. My tires are shot, so I can put just about anything on when I get to that point. I believe that I have widow makers on the back, so that will need to be replaced.

What kind of performance will this set up get me? When this project is completed I would like to drive it a bit, but nothing too far.

From what I've read the 4.88 is not very good for highway speeds. Could you guys enlighten me?

 

If the F250 has a standard 8 bolt lug pattern, I'd suggest finding a Dana 60 or 70 from a '57-72 F250. That way you can still run a stock sized tire on the front and back without worrying about clearance from either the front fenderwells, or the rear. I had 16.5" 8 lug wheels on my IH truck that came from a Ford of that era or so (clears the larger drum brakes). Typically, most Danas of that years came with either a 4.11 or 4.56 gear ratio. Not the best for highway, but tolerable up to 55mph.

 

It will be great for pulling stumps, but you won't keep up with traffic even in the "slow" lane on the expressway, or beat a kid on a tricycle away from a traffic light.

 

That's kind of what I was afraid of. Of course, my 12 year old has said several times that he could drive it to school when he turns 16, maybe that is a good reason to keep that rear.

 

My younger brother did with his '50 Chevy 1 ton. Didn't necessarily get all the chicks, lol. Despite being so slow anyone could keep up.

 

I'm in agreement with Ax/Havi.Though the Dana 60 is great,I really HAD to go from 4.56:1 to 3.54:1. I commute daily about 60 miles,and it was screaming at freeway speeds. If you don't live in a particularly hilly or mountainous area,you may even consider a 3.23(?):1 ratio.Mine cost about 375.00 (4 years ago) to have the gears changed.

 

IIRC the T98 is not syncromesh, so that makes shifting an "adventure" at every traffic light.

 

2nd through 4th are syncro-mesh,but not 1st.Most people I know seldom use 1st gear,starting off in 2nd.

 

The T-98 is probably one of the best 4speed transmissions ever made for light/medium trucks!!

Yeah. 1st is not, but the rest is.

I have a T-98 that came out of my 55 F-600 and if I wasn't going to do the automatic, I would be putting it back in.


I currently have a 6.80:1 rear axle ratio

That makes for some rather high RPM at highway speeds!!!

But I have 39" dia tires so the OD + 5.80:1 ratio that's going in will make up for that.






Your best bet might be to go to a newer axle with either a 4.11 or 3.73 etc ratio........and use either 16" or 16.5" wheels.....




Cheers,



Rick

 

Very interesting stuff. This gives me plenty to think about.
My initial plan was to leave the rear as it is. I probably need to reconsider that, although I don't plan on any long trips with it.... Always something to think about with these trucks.

 

Another reason to consider upgrading the rear axle is to get better and/or more modern brakes.

 

I also love the t98. They shift so smooth and its easy to shift without the clutch.

 

The 3.54 is a great gear for a pickup. I have that in my 85 F-250 with the stock 235-85x16 tires, and it'll do 70 mph easy turning only about 2600 rpms.

 

Great input guys. I hadn't thought too much about brakes yet. That would be probably the first non stock thing I would do with this guy... Guess I should start keeping an eye out for rear axles...

 

I think you will find the rear brakes on your current rear end is as good as any rear end you will find to install. If the current brakes are in good shape they would be as good as any drum brake no matter the year. Your ratio is low but not unusable. You have to remember someone has been using that truck with those gears for over 50 years and you can too. It just will have limits as to how fast you can drive it. I have a old international dump truck that is very low geared and is governed at 50 mph, so you just don't try to drive over 50. As long as your willing to accept the limits of speed you can drive your truck 20 miles or a 1000 miles.
Just another point of view.
Larry