8.8 swap....on the m-body?

prauk

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Anyone do the 8.8 swap on the M-body? I few members have been helpful in offering information on this but I figured I'd start a new thread.
1979 Lebaron.. and i have an explorer sport with the disc brake rear.
Lets talk.
 

beatersRus

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i was gonna go that way,
but i ended up going with Buds recommend of the 8-3/4 rear instead.
with the 360 magnum/904 in it now,i want to stick with 3:23 gears.
if i was gonna cut the floor and install an overdrive then id use the 8.8.
but this car is super low miles/38k and no way am i cutting it up.

i have 2 of these 8.8 with 3:73 gears and posi,ones a disc brake others drum.
so itll be interesting to see what the responses are to your topic.
the trick i found,was to have 2 of these,and take the one you want,cut the Long end of the housing to match the short end,cut off the flange and reweld the end back onto the now shortened rearend,and use the short axle from the other rear.
this turns the 8.8 into a normal center angle rear.

and an m body 8-1/4 rear for sale if you know of anyone who wants it.
no clue what ratio the 8-1/4 is yet.

ps,im still interested in those rims.
 
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Oldiron440

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I'm swapping one into my 64 Fairlane, I believe that the long side is 2 7/8" longer. On my 8.8 I had 3 7/8" removed from the long side and 1" from the short side. I had 9" ends welded on and I'm using aftermarket axles. I live an hour and a half from Quick Performance in Ames Ia so they do all my axle work. Without disk brakes I have less than a grand in the assembly.
In today's money less than a grand for an axle assembly with 3.73 gears, a locker and aftermarket axles with no C clips that's stronger than the 8 3/4 at a custom width is a deal!
Quick performance also welded the tubes the center and did a beautiful job.

I will say that the down side or at least something I don't like is there is no C clip eliminator kits for the Explorer 8.8 so I recommend the billet 9" ends and new axles. I removed all the brackets and unneeded barbs then sandblasted the housing and ran it through the parts washer before delivering it to Ames, I had it back in three days.

Here are 3 1/4" spring perches for the 8.8 from Calvert.
Screenshot_20200412-093958_Chrome.jpg
 
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Aspen500

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I know they make c-clip eliminator kits for the Mustang 8.8" but have no idea if they would also fit an Explorer 8.8" axle or are the axle tubes different?
 

beatersRus

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its the rear out of my 1981 2 door lebaron.
<<<<< silver car on the right.
slant six/column autocar,fairly unusual rear.
i do have a set of 410 gears to go with it.
 

8T2TOP

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Way too much of a hassle.
8.25 or 8.75 is NOT that difficult to obtain..
For all that jury rigging BS...
 

beatersRus

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Way too much of a hassle.
8.25 or 8.75 is NOT that difficult to obtain..
For all that jury rigging BS...
i agree !
lotta money and time for what,a limited slip 3:73 gear?

about the 8-1/4 part,
in the m bodies ive been buying it seems to be a rare option??
then again,if a b body 8-3/4 fits our m bodies then a b body 8-1/4 will too.
yes,no?
 

BudW

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then again,if a b body 8-3/4 fits our m bodies then a b body 8-1/4 will too.
yes,no?
Yes, the '68-70 8¼” will fit FMJ's.
Even the '69-70 7¼” will fit, as well – but not sure why someone would.
The '68-70 8¼” - sure.
The '66-70 8¾” is hard to go wrong with unless you have a High Output engine – which then a Dana 60 might be the answer (which '66-70 B-body D-60 is also a direct bolt in).
One important note is the propeller shaft lengths are different between all of the above mentioned differentials (bigger ring gear = shorter propeller shaft).


The only M's that came with 8¼” are: most (but not all) police cars.
Most (but not all) station wagons (same applies to F wagons).
Cars with a trailer towing package.
and lastly, special order cars.
Some 4-speed cars came with 8¼”.
I have also seen cases where factory ran out of 7¼” on assembly line and used 8¼” instead – but this is rare.

I would make an educated guess that 1 out of every 25, M's came with an 8¼” - but that is only a guess (the number might actually be smaller - but not higher).
BudW
 

Mikes5thAve

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360 cars also came with 8 1/4 for the years that was an available option.
When the majority of the civilian 80s Ms had 7 1/4 I'd say that it's a wider ratio then 1:25. I've lost count of how many junk yard cars I've seen over the years but know i've only seen a few with the bigger axle.

One word of caution or don't forget is the 7 1/4 had equal diameter axle tubes until 80 or 81. That throws a curve ball into things when some people think the equal lengths means it's 8 1/4 or that 81-89s with the bigger (3") axle tubes also means 8 1/4.
 

8T2TOP

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And early 80s 7.25 went to a 10 bolt cover which adds to the FUBAR..
 

Mikes5thAve

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ahhh whut ??
do tell,i thought i had a 8-14 and now you have just made me wonder.
did they keep the squared sides? like the former 7-1/4?

the newer style ones with 10 bolt cover has axle tubes that get narrower when they get to the center housing.
The older ones have smaller tubes.
 

Mikes5thAve

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I have seen more J bodies with 8 1/4 then M bodies.
Maybe some slightly performance cautious bean counter thought they had a stronger chance of being driven harder then a 4 door granny mobile?
 
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