rear end swap question

1949 f1 pickup.

It tops out at around 40-45. Would love to be able to leave the original flat head 6 and 4 speed in but would like to be able to go atleast 55 without the engine blowing up.

I have a line on a 1988 ford ranger.

Would it be easier to just swap out rear ends?

or

Can I replace the gears in the rear end to allow 55-60?

 

You'll lose out on low end grunt to gain top end. a wider ratio T5 will help. Lower 1st, 2nd gears mean you can run a conservative 3.73ish gear instead of the 4.56 or whatever you have, and still cruise in 5th at 65mph on flat roads.

You really need to plan it out though. Taller rear tires would get you the stated goal, cheap and easy.

 

A 57 to 72 F-oo 9 inch Ford rear end is almost a direct bolt in.
They are the same width as the 49 rear.
Even has the same wheel bolt pattern so you can keep your wheels. The 9 inch comes with many different ratios .. and car center sections interchange ( 28 spline tp 28 spline )

 

The first thing you should do, in my opinion, is grab your tape measure. Measure the width (backing plate to backing plate) of each rear end. You would want them to be pretty similar.

If the widths are the same, you could put the ranger rear in the f1. You will have to get a drive shaft made. While the length may very well work, the yolk will have to be changed so that you can bolt to the new rear end.

I'm not sure on this one, but I think the f1 would have a 5x5.5 wheel bolt pattern. I'm also pretty sure a ranger would have 5x4.5 wheels. Unless you changed something else, you would have to have different wheels for the front and back. This may not be a big concern to you, but it would require two spares.

If you want to replace the rear end, I would swap for something a tad more conventional. You have a Dana 41. A Dana 44 , 9" Ford, or 8.8" ford all came in the back of f-100 and f-150s over the years. All of which, I would guess, would have a similar width and would certainly have the right bolt pattern. Also, those rear ends came with gears all over the map and have greater after market support than your original, or a 7.5" from a Ranger.

Adam

 

Ok I am not even close to being a car person. Can you explain to me what a "T5" is?

I do like the looks of the 15" tires on the truck. How would taller tires help me with better speed? What size would I have to go to? I am guessing that would take away from the lowered stance of the truck.

No one has a gear kit or makes a replacement rear pumpkin that I can just swap out.

I sit behind a computer and draw all day long so this is all new for me.

 

There are lots of late 50's early 60's F-100 rear ends available. In my area they cost usually 100 to 200 dollars complete.



They are easy to change out. I have done this swap 4 or 5 times over the years.

.

 

T-5 is a Borg-Warner 5 speed found in many different vehicles, comes in both World Class and Non-WC versions. The ones found in S10 pickups are commonly used because of the shifter location being further forward than other versions.

 

Ok I now understand what is meant by T-5.

World class or Non-world class...that brings questions.

I am going to guess that it isn't a direct bolt on. You would have to modify alot of stuff to get the t-5 in place.

Will all this work with a flat head 6?

Wouldn't it be easier to swap in an automatic? Do they make a T-5 automatic?
wow I just said automatic...man I must be getting old. Maybe for the wife to drive.

So do you just sway out the whole rear end axle shafts, housing and everything?

Then your going to need to either shorten or lengthen the drive shaft.

I would guess this swapping stuff isn't going to be cheap. Especially since I don't have a garage or the tools to do it.

 

Scratching my head on this one, but I think I recall that '48 thru early '53 f-1's could be ordered with a three speed overdrive transmission... but they were mostly mated to flat head V/8's. I don't know about putting one behind a flat head 6, might be the same bell housing bolt pattern as a V/8, not sure. A bit of work, but the O.D. would get you to 60 mph easily. Beg, borrow, or buy a basic tool collection, you're gonna need 'em is this hobby.

 

I had a 52 f1 and it had a 9" from truck,but are getting hard to find around here.
I now have a 53 f100 with 4.11 and same problem.
I find the 67 Mustang 8" rear is close as i can get.but you loose the bolt patten.
57 to72 ford trucks are 61"
I may have to go the mustang route or chevelle.

 

Shaft the dang thing into 4th !! That truck will go a lot faster than 45 or so. Old cars and trucks are noisey ,sounds like things are going to fly apart. Not so ,hook up a tach and that engine in decent shape will turn 3500 without issues and that sould get you 60-65. You need to be running tires that are 27" or so tall,235-75X15 would be a good start.

 

A larger diameter tire gives an effectively taller rear end gear. The circumference is bigger, so one revolution makes the car go farther. You can put taller tires on the wheels you have and probably gain a couple hundred RPM.

No, I don't think it would be easier to swap to an automatic, and I don't know what you think you would be gaining by doing so. If its purely because your wife can drive a manual, she could certainly learn on your f1. Those really low ears make them hard to kill. There are countless options for swapping transmissions. It would be nice to have an overdrive, but that's quite an undertaking if you don't have a place to work and some descent tools. The only "easy" transmission swap is one that was original to the vehicle.

If I were you, I'd put a tach in the truck and see what kind of RPM it's actually turning. Although I don't doubt that it has low gears. I would find a set of used, larger diameter tires if a couple hundred RPM was enough. If that isn't enough, I'd get one of the rear ends I listed in my first post, with 3.08 gears or so, and slap it in there.

Another thing to consider is, at 65 mph, your brakes aren't going to be adequate. If its like most old trucks, the steering is pretty loose and you'll want to address it before you get in a wreck.

 

Thanks for the reply's. Definitely gives me some ideas and things to try.

Will have to find a tach and hook it up.

I wasn't looking to go 65mph. 55-60 would be the tops.

I will also ck on the tire size that is currently on the truck.

I love this site. Very helpful