I have a bone stock 1949 Ford F1. Where do I find which rear end ratio it has? Is there a data plate somewhere that has that information?

 

Check the back of the chunk. It might still have the tag on one of the plate bolts.

 

3.73 was the standard ratio, 4.27 was optional. Late-'50's also had a 3.92 option.

 

There is no tag on the back of the third member housing. I thought that maybe there might be an ID somewhere on the data plate.

 

Without a tag, you'll have to remove the rear cover and actually count to be sure. Look at the right lower corner of the housing. Is the number "41" there? Albuq is right. Most likely a 3.73. Can you get the truck above 60 mph under power on the highway? If so, I can pretty much guarantee its a 3.73 if the rear is a Dana 41.

 

The most sure way to know is to actually check. Block the front wheels so the truck can't more. Jack up one rear wheel. Release your parking brake and take the transmission out of gear. Rotate the jacked up wheel so that the valve stem is straight up or straight down (for easy reference). Using chalk or your preferred marking method make a line on the rear axle yoke and rear housing. Slowly spin the wheel two revolutions and count how many times the yoke spins (you spin the rear wheel two revolutions since the spider gears are doubling your revs with the other wheel on the ground). If your yoke spins about 3 3/4 times you have a 3.73. If your yoke spins about 4 1/4 times you have a 4.27. In the unlikely event that your yoke spins about 4 times, you have a 3.92. Report back with findings.

 

Well I looked again, cleaned it up a little bit, and found this tag on the back of the third member.

I am assuming that this means I have a 4.71 ratio?

It says "W 47 / 11"





Tag on the back of the cover plate

 

4.27:1
47 divided by 11 is 4.27. Down just to the right of where you took the picture is a cast-in "4x", what number is that?

I'm curious about the "W", never seen that before.

 

Does anyone still supply the 3.73 ring gear and pinion for the Dana 41?

 

I don't know about 3.73, but you can get new 3.54 gears. We had a discussion about those recently, thread here: https://www.ford-trucks.com/forums/1...nd-pinion.html

 

Thanks for the information 38 Coupe. I got on their website and found the gears. I sent them an email to verify that it will work in my '49 F1 Dana 41 with 4.27 gears. To get 3.54 rear end ratio would be awesome. With the 4.27 gears, the truck is really good only for around town driving.

 

I'm almost certain that all of the tags on the Dana 41's that I own have that W. I have no clue what it means.

 

I just ordered the complete 3.54 ring gear and pinion and bearing set from them. They really make it easy and they said that this should be a perfect bolt on (or "in") for the Dana 41 rear in my truck.

thanks.

 

Please post pictures of the gear swap. It will provide great information for other folks in your situation.

Glad I was able to help a little bit.

 

Will do. Hopefully I will have the new set before the weekend.

Thanks again for your help.