12-09-2009 10:05 AM #1
Replacement Rear axles that Fit 1946 Ford Coupe?
I am trying to replace my rear axle and still use the flathead v8. I want to be able to put the widest possible tires in the rear without having to mod the frame. I want to find a donor axle if possible. the rear will suspension will be upgraded to a bolt in leaf that will lower the rear 3-4 inches. Any help will be greatly appreciated.
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granted I have a gm driveline in my 47, but I'm running a 92 firebird rear with disk brakes and 17x9.5 rims and 345/45/17 rubber with no rubbing. I adapted a universal truck leafspring suspension to work on my car. you have a lot of room in those wheelwells
I just measured the width on the 46 Ford rear axle I have and it is 62.5 inches from wheel mounting surface to wheel mounting surface. Most of the info I have seen suggests circa 1969 Camaro rear axles to replace these as they are slightly narrower at 60 inches. I guess that is to allow some fatter wheels under there than the original 16 inchers. But I may actually go with a 79 Camaro rear axle under my 46 because they are easier to find and I may be scoring one in a 79 Camaro I am trying to buy. I will simply run inset rear wheels to make the tires fit where I want them.
Here is a very helpful chart of various rear end widths:
When you order custom wheels from someone like Vintique or Stockton wheels you can specify how much offset you want on the backside. For example, the rear end on my 23 is too narrow (S10 rear) so I ordered the deepest offset wheels I could get to move the wheels out. But on my 27 I am running a 68 Mercury Montego 9 inch rear that put the tires a little further out from the body than I wanted, so when I ordered those wheels I had the offset put to the inside of the wheels so they would set further in.
That is what I will probably do if I use the 79 Camaro rear under the 46. Once I get the rear in place I can figure out how much inset the wheels need to have to get the tires to set where they look good. The wheel people use the terms postiive and negative offset, and I always get the two confused, but if you just explain to the people who make your wheels how far you want the wheels to sit back they will build them that way.
Here, this site explains it much better than me..........
Last edited by Itoldyouso; 12-12-2009 at 12:33 PM.
I do it a bit different then most, and yes, it does cost a bit more... I pick out the wheels and tires I want and get them... This way I'm not stuck with an offset that doesn't look right, also, I prefer having the wheel center close to centered on the width of the rim, better for wheel bearings. You'll also have to decide on the brakes you're going to run, drum or disc and take into account the width required for the drum or rotor. Then, put the wheels and tires under the car with the car at ride height, measure between the inner mounting surfaces on the wheel and either find a rear end matching this dimension, or build one to this width... Costs a bit more, but I just hate having to "make do" with stock stuff that doesn't really fit or look the way I want it to.... Another bonus, when you're all done with the car and decide it's time to "go fast", you can bolt on a good hookin' set of slicks and not worry about breaking a couple of previously used and abused rear axles not designed for the horsepower I'm probably going to put to them, anyway.....
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Is there any draw backs to using the original rear end when i upgrade the engine in a couple of years?
Only if you decide to step on the gas pedal. Well actually these stock Ford banjos took some abuse in the early days, even on dragsters, but they did break often too. Keys in the ends broke and if the axle broke the wheel on that side would part company with the backing plate. They used to sell safety clamps that went over the edge of the brake drum so if the axle did break it kept the drum in place until you could stop (maybe)
With a moderate street engine and a sensible right foot lots of rods are running them, especially with the current "traditional" craze. But a nice 8 or 9 inch Ford or Camaro rear is much stronger and easier to get parts for when you are 500 miles from home. I have a 46 rear but will use it for an old timey modified and put something stronger under my 46.......I know how I forget and put my foot through the firewall way too often.
i dont see any. most likely a 3.73 though, but check your tag. if its a v8, it should be the trac-lock. it should also be a 31 spline. i dont see how you could go wrong for 275. the best parts about these rear axles is how strong, common and cheap they are.
as long as your happy with the width is all that really matters. as stated on the ranger station, the tube diameter is 3.25. when you order your spring kit, youll probably need to tell them that diameter so they can give you the correct spring pads.