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Welcome to FordPinto.com, The home of the PCCA => General Help- Ask the Experts... => Topic started by: LongTimeFordMan on September 20, 2020, 11:27:44 PM

Title: 4 bolt pinto 6.75 vs 4 bolt mii 8"
Post by: LongTimeFordMan on September 20, 2020, 11:27:44 PM
Hi..

I was wondering if there are any 8" rear ends that were fitted with 4 bolt wheels that would fit the 4 bolt wheels from a 73 pinto 6.75 rear

I may be able to get an 8" but would like to keep my  current alloy rims.

Thanks..
Title: Re: 4 bolt pinto 6.75 vs 4 bolt mii 8"
Post by: oldkayaker on September 21, 2020, 04:46:25 AM
The 74-80 Pinto and Mustang II both 8" and 6.75" rears have a larger hub size than the 71-73 Pinto's.  The Ford 71-73 steel wheels will not fit over this larger hub.  The after market aluminum wheels that I have used have a larger center hole so they fitted over the larger hub.  I do not know if the 73 Ford aluminum wheels have the smaller center hole or not.  Just roughly measuring the center hole on Ford steel wheels, the 71-73 center hole is 2.4+" while a 79 wheel measured 2.5+".
Title: Re: 4 bolt pinto 6.75 vs 4 bolt mii 8"
Post by: LongTimeFordMan on September 21, 2020, 12:26:48 PM
Thanks..

I have Americam Racing aluminum rims with the removable centers which i wanted to keep so i dont think that the center hub would be a problemsince i can wobble the centers when the lug nuts are loose when i install or remove the rims

I was mainly  concerned about the 4 bolt  lug pattern fitting my rims. My rims  have tapered lug holes and bolts so i assume that they locate on the lug bolts
Title: Re: 4 bolt pinto 6.75 vs 4 bolt mii 8"
Post by: oldkayaker on September 21, 2020, 03:24:48 PM
Nice looking wheels.  All stock Pinto's used 4 lugs on a 4-1/4" bolt circle pattern.  Note some of the 1960's Ford's used 4 lugs on a 4-1/2" bolt circle pattern, see link below.  From my experiences, the lugs will center the wheel.  My heavy stock GMC van uses the lugs to center the wheels and it came with tapered lug nuts for the stock aluminum wheels.  The after market aluminum wheels on my Pinto's were designed and use straight shank lug nuts to center the wheels.
http://www.teufert.net/wheels/bolt-pat.htm
Title: Re: 4 bolt pinto 6.75 vs 4 bolt mii 8"
Post by: Wittsend on September 22, 2020, 11:33:51 AM
Those wheels look late 70's early 80's - or even newer and I'd assume have the larger center hole. But if you take one off and measure the opening it should give a decent indication. The difference isn't much as Jerry stated. The pattern is 4-1/4" which also mated to the Fox body 4 bolt pattern.

 Just a note that I recall there is something different about the 8" rear and the parking brake cable. I can't remember if it is the attachment anchor or the cable length. So, you might either need to swap the cable or make sure you get the 8" brake cable. Hopefully someone else knows. I did mine 12+ years ago and my recollection just isn't what it use to be.

... And I recall there might be a difference in the axle tube diameter??? I think when I grabbed my 8" I basically made sure everything that was re-attachable I put back on before I went to the window to buy it. Again the memory is vague. I hate getting old!
Title: Re: 4 bolt pinto 6.75 vs 4 bolt mii 8"
Post by: 65ShelbyClone on September 22, 2020, 01:29:59 PM
I reused my '72 brake cables on the '77 rear end. Axle tubes are the same. Spring perches are not and you'll be money ahead to get the shock brackets and isolators to match them.
Title: Re: 4 bolt pinto 6.75 vs 4 bolt mii 8"
Post by: Wittsend on September 22, 2020, 03:15:12 PM
Thanks. That confirms the differences.  I'd rather say something (a warning) than not, but I hate that I often can't remember all the specifics. Glad someone could fill them in.

 My 8" came out of a Mustang II. Weren't the lower perch plates different? My 73 originally had the single threaded pin on each shock end. I just went and looked and the lower mounting plates on the later 70's Mustang II has two sideways holes to bolt through a circular hole on the lower Mustang II shock. Maybe that actually offers a better shock option? Anyway, I just thought I'd mention it. I think (but not sure) I just redrilled/mixed & matched my 73 plates??? Again, I just hate not remembering.
Title: Re: 4 bolt pinto 6.75 vs 4 bolt mii 8"
Post by: 65ShelbyClone on September 22, 2020, 04:35:48 PM
The MII brackets might require figuring out another shock absorber option then. I used the hardware from a later 2.3 Pinto and it was a bolt-on affair.
Title: Re: 4 bolt pinto 6.75 vs 4 bolt mii 8"
Post by: rob289c on September 23, 2020, 07:22:57 PM
Related Story:  I tried to mount the Pinto's 13" rims on the 4-lug 6-cylinder Mustang and they would not fit.  I thought for sure they would but they would not.
Title: Re: 4 bolt pinto 6.75 vs 4 bolt mii 8"
Post by: 65ShelbyClone on September 23, 2020, 08:49:37 PM
That's one of the 4 x 4.5" rear ends that oldkayaker mentioned. I think Mavericks might also.
Title: Re: 4 bolt pinto 6.75 vs 4 bolt mii 8"
Post by: Wittsend on September 24, 2020, 12:00:08 PM
Yes, the 6 cylinder Falcon/Maverick/Comet/Ranchero all used the 4 x 4.5 bolt pattern. The (early) Corvair, Datsun as well as others also used it. Today you will likely find it more in a metric 4 X114mm size. A lot of times you hear people say that the Maverick 8" will work with the Pinto. Most likely the person doing the swap is opting for 8" - 5 lug wheels such as the V-8 Maverick/Comet etc. had. I believe the Maverick 8" is also 1/2" narrower and I'm not sure if the spring pads line up perfectly. If the stock Pinto configuration is retained this poses a problem with spare tires (as in needing two). Therefore the simplest solution is to find a Pinto or Mustang II 8" rear end and IF you have 71-73 Pinto factory wheels they will not fit though there is some hope if they are aftermarket wheels.

So:
 71-73 Pinto's 4 X 4-1/4" pattern BUT, smaller center circle on the wheel.
 74-80 Pinto's (Mustang II) 4 X4-1/4" pattern  with larger center circle on wheels.
 60-77 /Falcon/Maverick/Comet/Ranchero 6 cylinder models, 4 X 4.5 pattern. Weaker than 8". Widths may vary.
 70-77 Maverick/Comet V-8, 8", 5 X 4.5 bolt pattern.  Not sure on all 8" widths.

Title: Re: 4 bolt pinto 6.75 vs 4 bolt mii 8"
Post by: 65ShelbyClone on September 26, 2020, 02:20:25 PM
I purposely mentioned the Maverick for that reason; it comes up frequently as a swap donor despite not being a direct replacement. The spring perches have to be modified and neither wheel bolt pattern is the same as a Pinto. The V8 one would probably be the shortest distance to a five-lug conversion although five-lug axles for the Pinto/MII 8" aren't impossible to find.
Title: Re: 4 bolt pinto 6.75 vs 4 bolt mii 8"
Post by: Wittsend on September 27, 2020, 11:22:50 AM
For sure, those wishing to convert to 5 bolt do benefit from the Maverick 5 bolt - 8" such as you have done. As the 8" gets harder to find I've heard that the Bronco 8.8 is another option but if I recall correctly the center section is offset (likely for the transfer case of 4 wheel drive). Too bad there isn't a universal site like WiKi where all aspects of transplant (rear ends, engines, transmissions radiators etc.) could be easily found for any specific car.
Title: Re: 4 bolt pinto 6.75 vs 4 bolt mii 8"
Post by: 65ShelbyClone on September 27, 2020, 02:34:01 PM
Yeah, the leaf-spring 8.8s have to be shortened on one side and the long axle swapped with another short one. They're good rear ends and many are Traction-Lok equipped, but I'm not crazy about integral carriers and c-clip axles.
Title: Re: 4 bolt pinto 6.75 vs 4 bolt mii 8"
Post by: LongTimeFordMan on May 29, 2021, 08:17:36 PM
UPDATE...

i have found an 8" rear end from a 1978 V6 pinto with an auto trans.

i understand that it will probably have 3.0 or 3.2 gears and i plan to convert it to 3.55.

I assume that since this is from a pinto the width will be the same as the 6.75 but my question is whether the late model housing will bolt directly in as far as the shock mounts, U bolts, pads, etc.

also would the backing plates, brakes etc from th 73 6.75 fir or should i use the entire 78 setup.. i can get the complete rear end setup.
Title: Re: 4 bolt pinto 6.75 vs 4 bolt mii 8"
Post by: Wittsend on May 30, 2021, 11:31:47 AM
When I went to a 8" rear end it was a complete (as they say) "drum to drum" swap.  This was about 12 years ago and I think it was $116 out the door at Pick Your Part.

The 6-3/4" brake drums will NOT work. The center hole is different. As I recall there was possibly an issue with the parking brake cable too. Maybe someone else knows better. I just can't remember. I believe my rear end came out of a Mustang II. As far as the pads, mounts, U-bolts etc. go I the 8" tubes taper down and I believe the original 6-3/4" pieces mounted the 8". Again I'm not 100% on that but believe it is good.

 The width is fine, no worries there. However, the centerline of the axle to the flange attachment of the driveshaft is different. I believe the difference is in the 1" to 1-1/2" range. So, the driveshaft is not the proper length. I was just very fortunate that I also went to a T-5, 5 speed and what was lost on one end was gained on the other.

As to ratios, the 8" Pinto rears came with 3.00, 3.40 and 3.55. There should be a tag bolted to the rear. Tire diameter and intended use/expectations plays a factor in what ratio is best.


Update: Actually as I (NOW) read through the previous post (should have done that before writing this post) I believe all these questions have been answered before. It would be beneficial to go back and re-read them.