Rear-end help here
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Elder User
Joined: Jul 2001
Posts: 525
Likes: 2
From: Deridder, LA
Rear-end help here
Okay Forders,
Here is the big one.....I found a 9" rearend from flange-to-flange 65"....From the outerlip of the backing plates 58-1/2"...the ratio is 2.50:1....and the casting numbers are 19753 with a date code of 7G21....on a tag it reads WGC-K 7HC 50-9 483A....don't know what it came out of but its $100 bucks....Can somebody tell me if this rearend will keep me from burning so much gas with the ratio and will it work on a 1954 ford truck with no mods?
James
Here is the big one.....I found a 9" rearend from flange-to-flange 65"....From the outerlip of the backing plates 58-1/2"...the ratio is 2.50:1....and the casting numbers are 19753 with a date code of 7G21....on a tag it reads WGC-K 7HC 50-9 483A....don't know what it came out of but its $100 bucks....Can somebody tell me if this rearend will keep me from burning so much gas with the ratio and will it work on a 1954 ford truck with no mods?
James
Lead Driver
Joined: Apr 2002
Posts: 8,813
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From: Littleton, New Hampshire
James,
Well, that's a very good price for a nine inch. However, first of all that rear is a little on the wide side since about 61 inches would be ideal although you could possibly make up the difference with wheel offset. Secondly, the ratio is too tall for a 3 speed straight stick transmission. You will almost have to slip the clutch to get moving unless you have a 4 speed with a granny gear. With the original engine and 3 speed transmission you want a ratio of around 3.25 to 3.50 but I'd say a 3.0 would be the abolute tallest ratio you could use. If you bought the rear with the idea that you could trade the pumpkin for something with a shorter gear you miight come out. A 2:50 gear would be okay for a large cubic inch engine with an automatic like a 460 with a C6.
Vern
Well, that's a very good price for a nine inch. However, first of all that rear is a little on the wide side since about 61 inches would be ideal although you could possibly make up the difference with wheel offset. Secondly, the ratio is too tall for a 3 speed straight stick transmission. You will almost have to slip the clutch to get moving unless you have a 4 speed with a granny gear. With the original engine and 3 speed transmission you want a ratio of around 3.25 to 3.50 but I'd say a 3.0 would be the abolute tallest ratio you could use. If you bought the rear with the idea that you could trade the pumpkin for something with a shorter gear you miight come out. A 2:50 gear would be okay for a large cubic inch engine with an automatic like a 460 with a C6.
Vern
Last edited by GreatNorthWoods; May 11, 2006 at 07:28 AM.
Hotshot
Joined: Oct 2004
Posts: 15,882
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From: Durham NC
Sounds like you found a Mopar rear end. I don't believe FoMoCo ever used a 2.50 gear in a 9". Out of the vehicle the two look similar, but the Mopar will have a pinion snubber (or at least the bolt bosses for one) on the nose of the center section.
Lead Driver
Joined: Apr 2002
Posts: 8,813
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From: Littleton, New Hampshire
Originally Posted by 55FordLover
my mistake on "NO MODS"..... i have a 302/AOD combo....
I still would not use a 2:50 ratio with an AOD however. You would probably not shift into OD until 65-70 or even higher. I had a 3:00 gear with a 700-R4 in a previous vehicle and it shifted into OD at around 65. With the AOD you want something in the 3:70 or higher range. The minimum I would use with an AOD would be a 3:50. My Dodge Dakota has a 3.92 gear with OD and it turns about 2000 RPMS at 60 MPH in OD.
Vern
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From: San Francisco, Ca.
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Senior User
Joined: Nov 2005
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I friend of mine has a '69 Mercury Marquis Brougham. I believe it has a 2.50 rear (posi). He got a ticket for 104 MPH...over the speed limit. The posted speed limit was 55. He has a 429 SCJ in it too!
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Senior User
Joined: Jan 2003
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From: ishpeming usa
The rear end in my 51 came out of a mid 70's Ranchero with 351W & C-6. This was manufactured during the arab oil embargo. It had a 2.50 when I got it; I scored a 3.25 before I installed it, so it may work well with the 351W C-6 if I ever get it on the road..
Later, Randy...
Later, Randy...
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Joined: May 2006
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9 inch Ford that fits right in the stock location
I'm just getting back into F-100's. I built a 53 back when I was 16-19. I'm 32 now. Anyway, back then I found a 67 F-100 with a 9 inch that bolted right in. I mean spring perches were same width as stock 53 F-100 leaf springs, overall width was near perfect. I bolted stock wheels on it and you couldn't tell it wasn't the original rear (dimensionally). It was a 28 spline rear with 3.50 gears. I think the truck it came from was a 3 speed stick, but that was a long time ago. Gears or the whole center section are pretty easy to change. I would assume there is a window of 1967 to 1970 - maybe 71 that would be the same? I remember checking out a 72 long bed pickup and it had 2 inch spring perches while the stock spring perches were 1 - 3/4" (I can't believe I remember any of this). Good luck.
