1949 dodge Rear end swap?

Hello All! So i have found several threads about rear end swaps but they seem to be done when a stronger than stock engine is used. I am keeping the original 230 flat six 3 speed in my '49 Dodge Coronet... so the question is, is there any gains from swapping the rear end? Speed, gas mileage ect...?

 

The primary advantage would be to gain a more highway friendly gear ratio. The rear axle in your car is probably 3.90, maybe even 4.10. That means the engine is turning quite a few revs when driven at highway speeds (65 mph or so). You could accomplish the same thing with an overdrive transmission however, and retain the lower (higher numeric) ratio for around town, but an overdrive for your Dodge isn't growing on trees, whereas a suitable rear axle is easily sourced. It likely will require some driveshaft work, both to accomodate the likely change in length required and you probably have the 'pot' type u-joints.

If your Dodge is a Gyromatic or Fluid Drive.......then I would think again about making any change unless it included a fully manual trans and clutch aassembly. For more info on these trannies, do a search of my posts........I did a rather lenghty explanation for another HAMBER a few weeks ago.......too lengthy to repeat here.

Ray

 

Modern brakes vs dual wheel cylenders is a plus. A 81/4 Mopar, 8" ford or 10 bolt GM would do. With an automatic tranny a 71/4 Mopar would work.

 

i wouldn't run a 7 1/4 i think the only things they should have been used on were the carbed 4cyl dakotas... i snapped the cross shaft of my 7 1/4 in my 90 120hp v6 auto dakota

 

The 7 1/4 is a little light duty.......but the Corporate 8 1/4 is a good axle for general use.

They can be found in a wide variety of Mopars but the one most likely
a good width would be the Jeep Cherokee version. They come in 3.07, 3.55, 3.73, and 4.10........6/stick, 6/automatic, 4/auto and 4/stick in that order.

8" Ford rear axles are also an excellent choice. A lot of people have 9" Fever and act like nothing else will do, but 8" er's are stout enough for anything but really high performace applications.

Ray

 

Way back I saw a line of Aspen/Volares in a junkyard. The 318/904s had 71/4, the 225 sticks had 81/4!

 

As much as people boo hoo the 7 1/4 I have the original one in my Valiant for over ten years and it has not grenaded yet, that is with a mild 318 and manual trans. They are plentiful and can be found with 3:23 gears.........
I don't think a flat six would hurt one........