They ran 8.25’s in 1/2 ton 4 wheel drive trucks with factory 440’s in the late 70’s.
Let’s talk about the 8-1/4” diff
- Thread starter TT5.9mag
- Start date
-
I really doubt that. First, the 400 and 440 went away after 1978. EVERY 1/2 ton 440 truck that I have seen has had the 9 1/4" axle.
Inertia
Well-Known Member
C-Clip
My son is a Jeep offroader, he mentioned an outer bearing kit avail to retain the axle like an 8 3/4, to prevent the axle coming out if the c-clip broke .
He once drove home with a sapling tied to the side of his Jeep, to stop the wheel/axle from walking out.
My son is a Jeep offroader, he mentioned an outer bearing kit avail to retain the axle like an 8 3/4, to prevent the axle coming out if the c-clip broke .
He once drove home with a sapling tied to the side of his Jeep, to stop the wheel/axle from walking out.
Well, the laughing was at they changed the name to 8 3/8... chuckle.... not at you
Actually.... the 440 didn't go away in '78. It hung around a while longer in RV's
I thought the 8 3/8" designation was strange too.
It's why I laughed...
WITH blocks that had casting dates no later than 1978.
I'd like to see a 400 or 440 with a 1979 or 1980 casting date. I've heard of the RVs with the 440, I've pulled engines from RVs too.
The 8 3/8 designation "usually" meant sure grip.Well, the laughing was at they changed the name to 8 3/8... chuckle.... not at you
which is odd in itself.. because our '80 D150 (drag truck) came with the "8 3/8", open rear and .... 2.71's !!!!
GM did similar. Their 8.5" rear was called a 8.625" when it was a limited slip.
I figured the 2.71's must have been ordered, because 3.21 was the "run of the meal" for any D100/D150 2WD
like_A_pike
that's not factory
I’ve beaten the poop outta mine for 15 years….
One good hook with 500ftlb of torque.
It is quite possible that I have not seen all of the oddball equipment that Chrysler stuffed into their cars and trucks.
The 8 1/4" axle was widely used and was a durable unit. I do try to refrain from stating absolutes, just that I have not seen them even though I've been junkyardin' and scrapping vehicles for a few years.
The 8 1/4" axle was widely used and was a durable unit. I do try to refrain from stating absolutes, just that I have not seen them even though I've been junkyardin' and scrapping vehicles for a few years.
What I highlighted is the bottom line. It was very, very reliable in all factory applications in which it was used. Even in the '73 340 Dusters with manuals.
TT5.9mag
Two atmospheres are better than one
Holy crap, great information thank you.
Healthy 385" stroker in a 66 Valiant Signet with 8.25" 3.21 gears and totally gets the dogs--t ran out of it everyday April to November.
Engine is hard on the body, but the rear end has been hanging strong for at least 15 years.
Tom
Engine is hard on the body, but the rear end has been hanging strong for at least 15 years.
Tom
Last edited:
TT5.9mag
Two atmospheres are better than one
Mine is in fact an 8-3/8” with factory 3:55s. Not a sure grip though unless it’s terribly worn out.
That's interesting. I wonder what designated the 8 3/8.
TT5.9mag
Two atmospheres are better than one
Me too, I’ve heard in a car it was an 8-1/4 and in a truck it was an 8-3/8. But they’re the same. Not sure how true that is.
Maybe that's the difference.
Oh and on this "big blocks were cut off in 1978". It's really sketchy. They continued for sure in 79 to use them in motorhomes and such. This is similar to the slant 6. In cars, 1983 "or so" was it for the slant 6, but trucks ran through 1987. They also ran until the year 2000 in other countries. What did other countries do for the big block? Similar, maybe? Similar also was the run of the early Hemi. 1958 marked the last year for the early Hemi production, BUT medium duty trucks have turned up a year or two later with them factory installed. Think 354 Power Giant.
Last edited:
Like I wrote, what I have seen and read is that while there were 440s available in RVs after 1978, they supposedly all had casting dates on the block no later than 1978.
I'm okay with being proven wrong on this if someone has pictures of a later casting date. I'm always willing to learn new things.
I'm okay with being proven wrong on this if someone has pictures of a later casting date. I'm always willing to learn new things.
I owned a 1977 1/2 ton 4WD with a factory 440 that had an 8.25 in it. Truck was all original. And I looked at another one that was ordered new that was very similar with an 8.25 in it. I, like you, was surprised there wasn’t an 8.75” in either of them. Ma Mopar did some weird stuff at times!!
The 8 3/4 axle was out of production by 1975. The upgrade from the 8 1/4" axle was the 9 1/4".
-
