Same with an 8.75. One under an early 6 cylinder A-body was weak as water. The hi-po units were much better.


So which 8 3/4 was the better one? 489,741,742?

You must not read... I said... heavy car or a 4
speed will break a 8 3/4.. they work great in LIGHT
cars

If anyone doesn't believe that 8 3/4 cases don't flex because of the lack of pinion support, look at the housing & the damage to it from the ring gear shearing teeth. This was done prior to the brace being welded to the housing. Dry hops, on & off the throttle at 20-30mph in 1st on the street showing off in my younger years claimed the ring gear that did this. The brace covers the worst part, not sure why the cap didn't break.
I am still running the 8 3/4 because i still have quite a few spare cases & only get to the track 1-2 times a year. As mentioned previously, billet caps & braces are just band-aids ... especially on heavy BB cars.
A 60 is in the future for my car, because it's stronger/more dependable.

Early /6 a-body's? 99% had 7 1/4 rears. My 3 speed /6 Twister has the 489. 741 weakest, 742 then 489 but of those two each has their good and bad points but neither will not hold up behind a 4 speed unless he has 675-14s, they where made with grease I think.

YOU`RE kidding right? Screw the "math" equations this and that bs. My old solid cammed 906 headed motor on Pettis`s dyno made 615 hp and 580+ tq. and went 10.40`s at around 3250 lbs. all day. So you`re telling me that a bigger better fully ported e-head and a 680-660 lift w/276-281 @ .050 solid roller and low drag back cut rings is making LESS hp.... Ya right. Put your motor in a street weight car like mine and get back w/me............

you are a silly man,Dyno's don't go down the track. your numbers don't add up to 700hp any way you look at it. you are 100 pounds heavier than my challenger I ran 130mph with a stock stroke 360 don't you think I would gain more than 5mph with 200 extra HP?

Stop it your hurting my feelings...........NOT! Some of you guys act like I`ve only made 50 passes or something. I have a stack of time slips from the 90`s up till now and use to T&T at L.A.C.R. almost monthly w/a warmed 360 then my BB and even showed Al Alguire my stack of slips when he was here. Back to building carbs and at the end of the year I`ll hit Bakersfield for my 9.60 or better and HOPEFULLY my lowly 8 3/4 lives but if it breaks which according to some it will, then I`ll put it back together and move on.......

If you we're making any real power you'd have broke that rear gear by now! (come on! thats funny no matter who ya are!)

The 742 is the best stock 8 3/4, the 741 will live very well in a medium weight, medium power BB A body My 440 powered 1969 Dart GTS weighed 3300 lbs with me in it and had many, many runs on the OEM 741 case and posi with the OEM 3.91 gears. That car went 11.17 at 122 MPH in Las Vageas in November many times the last time I raced it here The stock 489 case with the crush sleeve is the weakest of the three, the 489 and 741 have the same size pinion gear diameter size at the front bearing If you put a pinon gear spacer in place of the crush sleeve then it is as good as the 741 The 742 and Dana 60 pinion gear shafts are bigger diameter at the front bearing

It IS funny cos everyone I know drives a 9-second car on the street and ALL of make around 599 hp.............just crazy and don`t know how they do it.......

742 case with MW cap, ARP studs and ring gear bolts, back brace
8.93 @ 149 3050lbs with driver. 1.21 60'
I change out the r&pinion every 300 passes.
NEVER broke in 15 yrs of racing. (100 passes/year)

Hmm? 3200# car, 9.79 @ 135.5 ... takes around 590-600rwhp to do that, 700hp seems legit to me.

My ex car weighs 3220 currently. A while back the motor made 705 ish horsepower on a dyno with Best machine.
That motor went 9.62@ 140 on super stock springs.
That almost 5 more mph than the above. Huge difference

When I had the car( little bit different combo) it went 135@ 3350. I figured it made about 640-650 REAL horsepower.
135@ 3250 ISNT 700 horsepower, it's a great elapsed time, but it isn't 700. More like probably 640-645.

Naw, Quick said the "math" doesn`t add up........

it doesn't but keep telling yourself it does and one day you will believe it

whatever the case your car/chassis seems to be working PDG ...

That was my very first pass on new combo and carb was lean up top so there`s more there and now it`s 3050lbs. so a new best is comin soon........

I was running 11.35 with a 489 case in my 64 with the old 446". When we built the Dana I sold the 489. The 3.91 gears looked new yet with no wear. I was always told the 489 case was the good one. Now it goes 10.15 at 132 mph. What is that at a tad over 3600#? About 550 HP?

Nice!

And then some...