• DC Doug
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Topic: 9" Ford four link where 8" 3 link used to be...

So, as anyone at CMP with eyes and/or ears witnessed, the Parnelli Jones/Holman Moody Galaxie looked the part, sounded the part, maybe even cornered the part (cornered as expected, that is), BUT it certainly didn't fast the part.  In addition to some electrical gremlins at higher RPMs we also suffered from a 2.80 rear gear.  We ran the entire weekend in either 1st or 2nd gear.  Great mileage (check), pulling on a 20 year old VW Golf coming out of the corners (no check).

Found a mid 70's Lincoln coil spring setup 9" ford rear in Speedy's pile of cast-offs (it's HUGE (the pile, that is)) that we think has better gears (3.50?), but it is the newer four link setup unlike the '67 Galaxie's 3 link.  So, my question is, what do I need to do to swap this in?  We can of course MAKE it happen, but there's always a smart way and the hard way.  Please being helping smart, thankyouverymuch.

Any thoughts, suggestions or links to build sites/threads would be hugely appreciated.  If you help me make this simple I promise you laps in this car!

Speedycop/NSF Racing /Pinewood Dirtbags
'10 Summit, CMP3, Autobahn, '11 CMP1, NJMP, CMP2, Summit, G'man, Stafford, Charlotte, Autobahn, ECR '12 CMP1, NJMP, G'man, NHMS1, Summit, CMP2, NHMS2, ECR, '13 CMP1, ECR, Summit, NJMP, THill, CMP2, MSR, NHMS, Sears '14 Barber, Sears1, ECR, CMP1, NJMP1, BWillow, Sebring, CMP2, THill, Sears2, '15 Sears1, Barber, Ridge, THill, '16 Sears1
  • From: Davis, Ca
  • Registered: 2009-04-30
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Re: 9" Ford four link where 8" 3 link used to be...

Change the gears in the 8"   used sets are almost free...

Gosh, my business card says 'Tech Tyrant'
  • DC Doug
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Re: 9" Ford four link where 8" 3 link used to be...

Evil Genius wrote:

Change the gears in the 8"   used sets are almost free...

That's what I thought, but I'm not finding anything in the DC area or on fleabay.  The ring and pinion new are actually kind of expensive surprisingly (as compared to 9") + we don't have experience setting up the gears.  Hoping to find a chunk/pineapple assembly to just bolt in.

Speedycop/NSF Racing /Pinewood Dirtbags
'10 Summit, CMP3, Autobahn, '11 CMP1, NJMP, CMP2, Summit, G'man, Stafford, Charlotte, Autobahn, ECR '12 CMP1, NJMP, G'man, NHMS1, Summit, CMP2, NHMS2, ECR, '13 CMP1, ECR, Summit, NJMP, THill, CMP2, MSR, NHMS, Sears '14 Barber, Sears1, ECR, CMP1, NJMP1, BWillow, Sebring, CMP2, THill, Sears2, '15 Sears1, Barber, Ridge, THill, '16 Sears1
  • From: Kansas City
  • Registered: 2010-02-10
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Re: 9" Ford four link where 8" 3 link used to be...

Evil Genius wrote:

Change the gears in the 8"   used sets are almost free...

+1
Mustang IIs and some Pintos used 8" rear ends.  Hunt around for a '75 -'76 Mustang and you might find a 3.55 or 3.40 to swap in which is wayyy cheaper than swapping out the entire axle.

Greg
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  • Baron
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Re: 9" Ford four link where 8" 3 link used to be...

Lemonious Monk wrote:
Evil Genius wrote:

Change the gears in the 8"   used sets are almost free...

+1
Mustang IIs and some Pintos used 8" rear ends.  Hunt around for a '75 -'76 Mustang and you might find a 3.55 or 3.40 to swap in which is wayyy cheaper than swapping out the entire axle.

Most of the 8" came with a 2.79 ish gear.

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  • From: Hayward, CA
  • Registered: 2010-03-23
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Re: 9" Ford four link where 8" 3 link used to be...

Lemonious Monk wrote:

Mustang IIs and some Pintos used 8" rear ends.  Hunt around for a '75 -'76 Mustang and you might find a 3.55 or 3.40 to swap in which is wayyy cheaper than swapping out the entire axle.

Or change out the whole rear end, which might be easier that swapping out the gears.

I'd go search around on the web for
a. The part number of the Galaxie rear end, or gear
b. Cars that used the the same rear end, and see if one of those came with a better ratio.
c. fords in general with came with the ford 8" rear end. then go find the rear end ratios.
d. Check the Ford Forum (where ever that is) for swap-able rear ends. There are lots of people wrenching on cars these days that share information.  Its amazing what is getting posted to the internet these days. Just have to do a little investigation

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  • From: Kansas City
  • Registered: 2010-02-10
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Re: 9" Ford four link where 8" 3 link used to be...

Swapping out the pumpkin is easier than swapping an entire axle provided the diff you are putting in uses the same axles.  IIRC, 28 and 31 splines are what the 8" came with.
As for ratios, 2.79 was the most common but 3.00, 3.18, 3.40, and 3.55 were also offered.

Greg
Team Skid Steer
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8 Reply by DC Doug (edited by DC Doug 2011-03-04 05:23 PM)

  • DC Doug
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Re: 9" Ford four link where 8" 3 link used to be...

Strangely, they actually had a 2.79 and a 2.80 ratio. 

So, even the fullsize cars (like the galaxie) had the 8" if they had the six cylinder or the 289 or 351 (the smaller 8's as long as it wasn't a hi-po engine option).  The hi-po and all the high displacement engines... 390, 427-8-9 had the 9''.  I think (read) all the 8'' were set up for 28 spline axles;  the 9" diffs were set for either 28 or 31 spline axles.  If it was a truck it was 31 only.

Great idea on searching for a specific ratio... getting much better results (more hits, but less noise) looking for a ''ford only'' ratio like the 3.40 as opposed to searching for 'ford 8 inch diff/chunk/axle...'  Still looking for a chunk/diff to just swap in as opposed to a full axle, but I finally found some (relatively) cheap ring/pinion sets on ebay, so if we can find someone who can set this up on the cheap that'll be an option.

Thanks guys!

Speedycop/NSF Racing /Pinewood Dirtbags
'10 Summit, CMP3, Autobahn, '11 CMP1, NJMP, CMP2, Summit, G'man, Stafford, Charlotte, Autobahn, ECR '12 CMP1, NJMP, G'man, NHMS1, Summit, CMP2, NHMS2, ECR, '13 CMP1, ECR, Summit, NJMP, THill, CMP2, MSR, NHMS, Sears '14 Barber, Sears1, ECR, CMP1, NJMP1, BWillow, Sebring, CMP2, THill, Sears2, '15 Sears1, Barber, Ridge, THill, '16 Sears1

9 Reply by RichVS (edited by RichVS 2011-03-04 09:23 PM)

  • RichVS
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Re: 9" Ford four link where 8" 3 link used to be...

Sniff around your local mini-stock circle track guys.  New R&Ps are available for $190, so with appropriate depreciation for used stuff you should be able to find a mustang II chunk for Lemons money.

edit:  http://www.speedwaymotors.com/Ford-8-In … ,3760.html

Brrrrrrrrrrrrrrrrrrr.

RichVS's Website

10 Reply by DC Doug (edited by DC Doug 2011-03-04 10:30 PM)

  • DC Doug
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Re: 9" Ford four link where 8" 3 link used to be...

ZOMG... mind is blown.  1930's FTW!!!!

http://www.youtube.com/watch?v=K4JhruinbWc&NR=1

http://i1005.photobucket.com/albums/af172/kirchbed/diff.jpg

Speedycop/NSF Racing /Pinewood Dirtbags
'10 Summit, CMP3, Autobahn, '11 CMP1, NJMP, CMP2, Summit, G'man, Stafford, Charlotte, Autobahn, ECR '12 CMP1, NJMP, G'man, NHMS1, Summit, CMP2, NHMS2, ECR, '13 CMP1, ECR, Summit, NJMP, THill, CMP2, MSR, NHMS, Sears '14 Barber, Sears1, ECR, CMP1, NJMP1, BWillow, Sebring, CMP2, THill, Sears2, '15 Sears1, Barber, Ridge, THill, '16 Sears1