Ford's standard rear end with a 3 speed back in the mid to late 50's was a 3.55. A 3.00 will be hard on the clutch from a stop sign while better on the highway. I have a 3.55 in my T-Bird that I would gladly trade for a good 3.89. Drag racing is more my game.

with a 3.00:1  27" TH (tire hight) going 60 mph you would be turning 2240 rpms.

with               28"                     going 60 mph you would be turning 2160 rpms.

with a 4-speed and granny 1st  you could get buy in this neighborhood easy enough, and tire height will help some.

-Gary Burnette-

Or, you can go to:

www.angelfire.com/fl/procrastination/rear/html

and play around with the numbers.

Butch Lawson

Manchester,  TN

salf100,



The 3.55 work good for me but if you do a lot of highway driving you may opt for the 3.25's. I do mostly town driving. My 3.55's are in a '55 Ranchwagon with C-4 trans and 27" tall tires. By rearranging the formula you can try different MPH and Gear ratios to check RPM; mph x gear ratio x 336 / tire diameter=rpm.

Example; 70 x 3.25 x 336 / 27 = ~2800 RPM or lower (numerically) 70 x 3.00 x 336 / 27 = ~ 2600 RPM. Just to confuse things, you could also lower the RPM by putting on a taller tire. (I know, you didn't ask that but thought I would throw it out there, anyway, haha).



Clear as mud, right??

"The Master Cylinder"

Enjoying life at the beach in SOCAL

It won't be ideal, but it will get back some of your truckability with the granny 1st gear and a tall rear gear. Keep in mind that with the stock 4 speed, 2 - 4 is the same as your current 1 - 3. But really, if you're considering this, save money and do a 5 speed and don't touch the rear gears. You'll have pretty much the same amount of work involved, actually it'll probably be easier because then you don't have to mess with the rear gears.



Stock 4 speed, you'll need to:

change the bellhousing

cut a hole for the shifter and possibly even clearance the floor for the transmission.

maybe change the drive shaft length

possibly change the clutch while you're there.



5 speed:

Different, modified bellhousing

cut a hole for the shifter

shorten the drive shaft

replace at least a couple clutch components.



You see, it's very much the same. and when compared to the 3speed, a 5 speed will give you a first gear which is like going up numerically by 1 or 2 ratios in the rear, a 4th gear to play with which makes it more fun and is sometimes more practical on slower roads, and a 5th gear that gets you better mileage on the highway. The 5 speed probably will cost a little more but you also get a whole lot more.


Lawrenceville, GA

I forgot to add 28 spline.

-Gary Burnette-

I have a 3.10 9" I would swap. I in Asheville, N.C.

-Gary Burnette-

I now have a 4.27 rear which I really like. When I'm in overdrive the effective gearing is 3.00. I can now start out in overdrive 1st, but I haven't tried it on a steep hill. I think 3.25 would be better. With the old rear 3.92 and overdrive the effective gearing was 2.43. I couldn't start out in overdrive 1st unless I was pointed downhill.

  Dennis in Lititz PA

I have 6.70X15 tires (27"). Ill look and see what size splines I have, 28 sounds right. And swapping the trans is not an option right now. I will trade anyone who wants to. I was thinking 3.25ish should be good. Better than what I have! Master, 3.55 work good for you? what vehicle are you running them in? The truck is lowered and not used to haul anything. Would a stock 4 speed be ideal? And what would a used 4 speed cost?

1964 F100 292YBlock

A stock '64 will be 28 spline. Check the axle tag to find out just what you have; it could be a 31 spline by now.


Lawrenceville, GA