8.25 Strength

-
JGC403

JGC403

Well-Known Member
Joined
Nov 22, 2010
Messages
1,046
Reaction score
48
Location
Baileyton, TN
How much power can the 8.25 handle? What usually breaks first in it? Is it worth adding a truss to it to stiffen up the housing? Street/Strip vehicle, so slicks at the track, with Sure Grip or some type of locker, behind a built 440.
 
They will hold a lot of power. Have a friend who had one in a Demon that left with the tires a foot in the air runnin strong 11s. Several seasons. Only reason he pulled it was because he upgraded the whole car lookin for 10s. He never broke it. In fact, he still has it. lol
 
You can break anything if you try hard enough. Im not bashing the 8 1/4 but if your spending all the money to hit the track, Ide upgrade when you can. Just my opinion.
 
They have their place & the strip is not one of them, imo. Mine is rebuilt with Auburn posi, Richmond gears, new bearings, etc. In a street 4 speed car, I've had to replace the adjusters twice in a couple thousand miles. Now they were all tough miles & several track passes with street tires. Maybe the backbrace would help. Personally I wouldn't spend too much on one. I'd put my money towards a 4:10 Dana from a truck. At least it's pretty much a one & done deal with these.
 
I would not run an 8 1/4 behind a 440.... I am running a 8 1/4 with my 360 though, I actually am upgrading to a suregrip 8 1/4 as we speak.
 
Back in 1982 we put a 5:30 geared, sure-grip 8 1/4 in my 13.5:1 comp 340. Snapped an axle the first weekend. Snapped the other axle & spun the backing plate the next weekend. Fixed it, sold it & put in a 5:13 geared 8 3/4. Never had any more trouble. [4 yrs of hard thrashing].
 
It's a little more involved for any rear drop out housing to add a brace.

A built 440 leaves a lot for interpretation of built.

You can't get 31,33 or 35 spl so you're already limited to somewhere around probably 4000 to max 5000 ft lb area, so if you're making 450 ft lbs and have 4.10's you're in that neighborhood of gambling.
.
 
The truss I would make myself, so wouldn't be spending to much extra money on it. And I was thinking having it go across the top instead of across the back like on 8 3/4. Like this, in the pic its on a truck but same idea of what I was thinking.
31723440006_large.jpg
 
Trusses are for the bending forces on trucks running baha like courses or stadium type events, trusses deal with keeping the tubes from bending just enough that they break the center-section.
Mostly a common issue on the front axles than the rear since the spring location is way inboard of the tire do to the steering knuckle and it has a large leverage point to snap and bend the tube out of the housings center-section by cracking them.

Braces deal with the leverage effect of the spring/suspension location in relation to the housing bearings from it to stop the flex from eventually prying out the carrier, the above may help slow it if you HAVE the power to, BUT that 8.25 will go thru axles LONG LONG before you EVER get to break the housing from lack of brace.

Adding anything in that form to a 8.25 would be a total waste of time.
.
 
I know with a Sure-Grip they will take alot on the street. I beat on mine with a mild 440 and it was fine when I sold the car.

I would be really nervous with either a stick or slicks though.

Coming from the 4x4 world, I would just do the 8.75 or 8.8 etc. swap. I used the 8.25 because it was a great deal and came all set-up. It is a decent rear, but there are better options out there.
 
don't be shy to abuse these. I ran 12.0's in my 3800 lbs R/T with a 8-1/4''. another guy I know ran 11.60's with his RoadRunner. he had a stout 440 big block. both cars were running slicks. 60' in the 1.60 range
 
Supershafts said:
Trusses are for the bending forces on trucks running baha like courses or stadium type events, trusses deal with keeping the tubes from bending just enough that they break the center-section.
.
Click to expand...

Not saying your wrong, just pointing out that there are braces for the 8&3/4 and I don't see to many of them under trucks. So there has to be some benefit for car applications.
 
i ran an 8 1/4 foryears in a alum headed full weight a body ran mid tens in the quarter but it had a spool and good axles that in the trick, I ran two sure grip units and they worked great until it went in the low 12's or so and slicks, the clutches started slipping with slicks on then so its accordind to your set up:D
 
JGC403 said:
Not saying your wrong, just pointing out that there are braces for the 8&3/4 and I don't see to many of them under trucks. So there has to be some benefit for car applications.
Click to expand...


Trucks use trusses for totally different reasons

Trusses, across the bottom or over the top, they defeat the flexing & bending up or down forces from landing and having all the weight of the vehicle on one end of the axle

Bracing, across the back or front, they defeat the flexing and bending forces forward and back.

The benefit of taking that particular item from the off-road world wouldn't help in the racing world
 
Been there/done that...I ran an 8 1/4 with slicks at the track and a 4 speed.I snapped an axel going 1..2 shift...wheel and axel passed me(450hp sb).C-clip eliminators will hold an axel in after breakage.Plan ahead $$,get an 8 3/4 or Dana 60 if racing is in your future.
View attachment Picture 010.jpg
 
I have ran an 8 1/4 in my 440 duster for 30 years with street tires. Holding up to 500 hp. and lots of torque! I once considered a change. If I were to go to the drags often maybe I would.
 
You must log in or register to reply here.
-

Back
Top