8 1/4 rearends

[72charger440]

i was wondering what should i do rebuild my 8 1/4 rearend and put a suregrip in it with 3.55 gears or should i buy a 8 3/4 and build it the same way? what would be better. and one more question would my stock 8 1/4 be fine running with my  400 hp or should i rebuild it nowor get the 8 3/4 and rebuild it b4 i drive the car?

thanks 

[A383Wing]

I say go with the 8-3/4" unit...much stronger and easier to find and get parts for

[72charger440]

right the only prob with that i cant find a 8 3/4 rear anywhere in my town or in a near by town  . so its going 2 be hard 2 find 1 and 1 for a good price.

[69bronzeT5]

Try to find a 8 3/4. I have a 8 1/4 in my '69 but I'll be switching it for a 8 3/4. There's no way the 8 1/4 will handle my 383.

[72charger440]

right if your 8 1/4 rear cant deal with your 383 for sure my 8 1/4 rear wont like my 440. dang when i go 2 mopars at the strip this month i need 2 find a 8 3/4

[Beer]

I just scored a 8 3/4" for $550,  Has a 3.91 SG (the guy who sold it to me knew what he had).  Its at Outragesouly Vintange now (shop in Maine) getting a DR. Diff disk Brake kit and Green Bearing pack installed as well as a new clutch pack.  Total for the 8 3/4" (not counting the Disk Brakes/Green Bearings) $800 (axle + teardown and reassembly w/ some new parts). 

Should have some before and after pics Tuesday 

[doctorpimp]

That's a good deal Jim!

Used centre sections with 3.91 SG (cone) go for around $350 +/- alone.  And finding a local one will save $75 shipping anyway!

[doctorpimp]

Yeah, back to the question LOL

Go for a 8 3/4!  You'll have to get a new driveshaft anyway with a BB and 8 1/4 due to length differences.  And since you're rebuilding the 8 1/4 you're not saving that much dough...  Search Moparts as well for a complete rear for a 71-74 car.  You could even use the 9 1/4... try to get the driveshaft too

Ma Mopar didn't use 8 1/4 behind big blocks for a reason - and that was when they were new!!! 
Sometimes even then, then the 8 3/4 wasn't enough - that's why the Dana 60 was in some cars.

[72charger440]

thats wierd mamopar didnt put 8 1/4 rear in big block cars then my rearend that came with my car is not the factory 1 then because my charger came and still has its factory 440

[69bronzeT5]

Not to question what you know or anything but are you sure its a 8 1/4?

[72charger440]

yeah i do i think.. dont the 8 1/4 have the cover plate on the back like the dana 60s and the 8 3/4 have the pumkin correct so it unbolts from the front unlike the dana 60s.

[69bronzeT5]

 

[72charger440]

yup. so i have the 8 1/4

[69bronzeT5]

Sounds like somebody swapped it out.

[Charger1973]

They definitely did put the 8 1/4 in big block cars, ive had several 73s with the 400 in them and they all had the 8 1/4 under them.

[doctorpimp]

Yeah sorry - the 400 2bbl cars had 8 1/4 rears - duh brainfart I parted one out 2 years ago - was upset that it wasn't an 8 3/4...

But a 440 car and 400 4bbl and 340 would have had an 8 3/4.

Maybe you have a 9 1/4?  See pic above...  Bolt on rear cover just like the 8 1/4 and Dana...

[bordin34]

Was the 9-1/4 available in 72?

[doctorpimp]

Dont think so, but maybe the 9 1-4 was swapped in

[Foreman72]

i also will b swapping my 8 1/4 for a 3/4...hopefully w/ an SG and 3.55s...has anyone ever seen them being sold w/ say...R/T 6 leaf springs on them...in good shape? and does anyone besides moser sell an aftermarket rear 4 mopars?

[72charger440]

yeah 1 the i have is for sure a 8 1/4 i put up a pic later of it but its deffinatly  an 8 1/4 mayb someone did put that rearend in my car but y get rid of an 8 3/4 but the way everthing is in my car looks like the rearends never been messed with but unsure.