8.75 rear end with 440 4 speed?

[Jay Williamson]

Hello,

I have a 67 RT with a 440 big block, 4 speed manual, and a 8.75 rear end. Was this combo ever offered? I thought all of the 440 4 speeds came with Dana60 sure grips

Thanks in advance

 

[JimCoronette]

8 3/4 with 440 Auto.
9 3/4 Dana with 4 speed.

Was it originally an auto car?
If not someone pirated the Dana.
OR they ran out of Danas on that day and threw an 8 3/4 in it to keep the line moving.

 

[Ceedawg]

It certainly wouldn’t have lasted this long if it came from the factory like that. First good sticky tire, boom!

 

[Cranky]

It certainly wouldn’t have lasted this long if it came from the factory like that. First good sticky tire, boom!

Oh I dunno about that. A buddy and I ran a 440/4 speed road runner at the track and we didn't start having problems with the 8 3/4 until it started going low 11's. Low 11's ain't all that fast but launching at 6k isn't too easy on those

 

[Jay Williamson]

8 3/4 with 440 Auto.
9 3/4 Dana with 4 speed.

Was it originally an auto car?
If not someone pirated the Dana.
OR they ran out of Danas on that day and threw an 8 3/4 in it to keep the line moving.

Unfortunately, I don’t have the build sheet. I suppose it could have originally been an auto on the floor car, but I cant tell since the floor pan was replaced. I just wonder if it will hurt to drive it with a 8.75. Wish I could find the build data based on the VIN number

 

[R/T Boy 67]

Contact Chrysler historical, with your VIN and the body codes. They might be able to fix you up. They have a lot of info on 67 and earlier cars.

 

[SGTPaul]

You can contact the Chrysler historical services. They have all the IBM punch cards up thru the 67 model year that were used to create the fender tags. Someone tossed all the cards from 68 model year on so no good for me. Good luck!

 

[moparnation74]

I just wonder if it will hurt to drive it with a 8.75

NO......it is a tough rear.....

4spd 440 = dana only......

Certicards ended in 1968 btw......

 

[Monkeymaster]

8 3/4 is a strong piece.
Drag racers used them in their front engine dragsters.
IMO you would be fine on the street.
Strip ?
That depends on HP, tire size, type of tire, drag slicks ect, and how sticky the track is, ie traction compound, temp ect.
MY 69 Charger has 18 spline , original w the 383, 383 is gone, 440 now spins the tires.
I have no issues, and yes I have run it on the strip.
Good luck with what ever you do.

 

[zyzzyx]

The biggest problem is that the ring gear deflects in the 8-3/4 and that is the death of it.
I used to see guys in the old days weld a large fine thread nut to the case and put a brass bolt
in it directly opposite of the pinion gear with about a 0.005 gap to support the gear. Put an auto
in it or put a Dana in it if you plan on hammering it!

 

[Stroker68]

Oh I dunno about that. A buddy and I ran a 440/4 speed road runner at the track and we didn't start having problems with the 8 3/4 until it started going low 11's. Low 11's ain't all that fast but launching at 6k isn't too easy on those

Pretty sure the max wedge cars had 8 3/4. Strong enough I guess.

 

[moparedtn]

I've had several 440/4speed cars over the decades and none have had the Dana
(yes, none of them were originally 4 speed cars).
To date, I've never broken an 8 3/4 - and I've done the usual stupid s%^&&^ we all have
with these cars.
For a street car like the OP is talking about, it'll be just fine.

 

[Jerry Hall]

Unfortunately, I don’t have the build sheet. I suppose it could have originally been an auto on the floor car, but I cant tell since the floor pan was replaced. I just wonder if it will hurt to drive it with a 8.75. Wish I could find the build data based on the VIN number

it will be fine, as long as you don't try to run slicks on a well prepped track. When I was 20-21 I didn't have a 440, but I did have a highly modified 383, that had a best time of 10.92 at 127 mph. Once I cured the clutch problems, the problems moved backwards to the U joints and rear end. I changed the driveshaft to the bigger U joints along with the yoke. I never broke a 8 3/4, but I did spread several yokes. The only problem I had transmission wise with the 23 spline was a busted shifting fork. I launched at 4000, had 30" tall slicks, and 4.30 gears. Shift points were at 7000 RPM's.

 

[Jerry Hall]

Hello,

I have a 67 RT with a 440 big block, 4 speed manual, and a 8.75 rear end. Was this combo ever offered? I thought all of the 440 4 speeds came with Dana60 sure grips

Thanks in advance

They did.

 

[Ceedawg]

Oh I dunno about that. A buddy and I ran a 440/4 speed road runner at the track and we didn't start having problems with the 8 3/4 until it started going low 11's. Low 11's ain't all that fast but launching at 6k isn't too easy on those

IF the tires hook, history. Low 11s is just a number, you can have a 600hp and run low 11s, by not hooking off the line.

 

[Cranky]

IF the tires hook, history. Low 11s is just a number, you can have a 600hp and run low 11s, by not hooking off the line.

The car hooked. We were working on getting it into the 10's to run the Super Street wars back then which was a fairly new heads up .90 class at the time. We ran across a good pair of 14" slicks and mounted them on 10" tims (all we had....very tight budget car) so they allowed a little bit of a soft hit. Thing is, they grew pretty well on the top end and with the gear the car had, the growth helped. At about the same time, ladders went on and so did a 60 after breaking the 3rd 8 3/4. And we weren't even close to 600 hp.

 

[Ceedawg]

The car hooked. We were working on getting it into the 10's to run the Super Street wars back then which was a fairly new heads up .90 class at the time. We ran across a good pair of 14" slicks and mounted them on 10" tims (all we had....very tight budget car) so they allowed a little bit of a soft hit. Thing is, they grew pretty well on the top end and with the gear the car had, the growth helped. At about the same time, ladders went on and so did a 60 after breaking the 3rd 8 3/4. And we weren't even close to 600 hp.

So, 3 8-3/4s, they do break then, you agree with me thanks

 

[Cranky]

So, 3 8-3/4s, they do break then, you agree with me thanks

Never said they didn't break.....but never broke one in a street car even with a 4 speed.

 

[Stroker68]

it will be fine, as long as you don't try to run slicks on a well prepped track. When I was 20-21 I didn't have a 440, but I did have a highly modified 383, that had a best time of 10.92 at 127 mph. Once I cured the clutch problems, the problems moved backwards to the U joints and rear end. I changed the driveshaft to the bigger U joints along with the yoke. I never broke a 8 3/4, but I did spread several yokes. The only problem I had transmission wise with the 23 spline was a busted shifting fork. I launched at 4000, had 30" tall slicks, and 4.30 gears. Shift points were at 7000 RPM's.

Seen some very strong 383s myself. Screamers. Always believed a 383 could make the same power as a 440 but at a higher rpm.

 

[Jay Williamson]

8 3/4 is a strong piece.
Drag racers used them in their front engine dragsters.
IMO you would be fine on the street.
Strip ?
That depends on HP, tire size, type of tire, drag slicks ect, and how sticky the track is, ie traction compound, temp ect.
MY 69 Charger has 18 spline , original w the 383, 383 is gone, 440 now spins the tires.
I have no issues, and yes I have run it on the strip.
Good luck with what ever you do.

Street only. I’m not Racing it