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Canadian Poncho Homepage -> Canadian Poncho -> Beaumont Power Train Tech Forum -> Stock 68
Post Info TOPIC: Stock 68
JJ


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Stock 68
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I was thinking of buying another rear end but I want to go original. I have 12 bolt 373s in now and I want to do some hwy driving and was thinking what hwy gears came with SD 68 Beaumont any body have any recommendations? 

 



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4SPEED427


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What transmission do you have?

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1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles 

1966 Grande Parisienne, 396 1 of 23 factory air cars (now converted to a "factory" 4 speed)
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cheetah 427


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331 is a stock ratio i think for the 68 SD

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2drpost


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3.31s



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4SPEED427


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Where the 3.31's in both auto and manual cars as the standard ratio?

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1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles 

1966 Grande Parisienne, 396 1 of 23 factory air cars (now converted to a "factory" 4 speed)
JJ


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Auto turbo 400


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JJ


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Thx guys looks like I'm looking for a spare rear end with them gears

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427carl


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I would go 3:07biggrin  for highway   (2 cents)     or 3:31 if you can score some



-- Edited by 427carl on Monday 28th of April 2014 07:38:54 AM

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JJ


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Are they hard to come by?


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4SPEED427


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Agreed, if you are running an automatic with no lockup converter (as in a TH400), the 3.07 12 bolt ratio would be bearable.

I ran 3.31 with the tallest 14" tire I could buy and at 70 mph that was too much rpm for my liking if I was on the highway for any length of time.

It certainly will reduce the launch feel though if you have 3.31 or 3.55 now. If you don't care too much about bottom end, I go as far as 2.73 to make it highway friendly. I hate a roaring engine on the highway. All these new vehicles with high ratios and overdrives and lockup converters have spoiled me. I used to think close to 3000 rpm at highway speed was no big deal but it sounds awful now.

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1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles 

1966 Grande Parisienne, 396 1 of 23 factory air cars (now converted to a "factory" 4 speed)
lueger68


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You should hear my car Carl at 4500 RPM at 95 KM on the highway with my 4:56 gears , it's just plane insane! I have a set of 3:91 gears I am putting in as it's a GM gear I bought off a rear end shop. Not sure what they would have come in though but it's the lowest gear I can run on my 4 series carrier. I would love to run a 3:31 set up in my 12 bolt but just don't have the extra cash presently.

Good luck JJ with your set up

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65 SD L79


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will a 4 speed auto change the final ratio?



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427carl


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70 SS ACADIAN wrote:

will a 4 speed auto change the final ratio?

         Yes     4th is normally about 30%    so 4:10 would be  2:87        our 83 S10 has  4:10 with 700R  



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68sd396rag


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the stock 68 sd 12 bolt rear end ratio were 3.07/3.08 I have removed several of them over the years

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rabbit64cs


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my 68 SD came with 2.73 open 12 bolt.

 

I have a 3.31 posi 12 bolt stashed for it wink



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later...rog

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I'm a collector...not a builder!!Located in sunny central Saskatchewan at the lakehead!
ZAPPER68


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JJ wrote:

I was thinking of buying another rear end but I want to go original. I have 12 bolt 373s in now and I want to do some hwy driving and was thinking what hwy gears came with SD 68 Beaumont any body have any recommendations? 

 

Hi JJ...

Another option you might consider is a 5 speed transmission.  I have 373's in my '68 Z28 and with a Tremec 5 speed (.68 o/d) the rpm was reduced from 3200 at 60 mph to 2300. this of course depends on what your wheel & tire combination is.

Just saying....



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1949 Pro Street Meteor Coupe, 468 BBC, 4L80E, Narrowed 9" 3.50 posi

1966 Biscayne post, 427 L72, M21, 4.11's 16600 original miles

1966 Hemi Satellite 4 gear 59K original miles
1968 Z28 302MO, M21, 3.73's, cowl plenum induction

1969 Ranchero 428 SCJ 4 speed
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