I have a chance to get a 741 case and gears (open, 3.23) for $50. Since the pinion is 1.375 in diameter, how much oomph will this take? I have a Aug 70 340 with a six pak combo, pocket ported x-heads that I will use on this. Probably a bigger cam also. Will eventually move to 3.55 gears, but now stay with the 3.23. How much power does this case with that small pinion handle? Thanks.
741 v 742 v 489 housings
- Thread starter Louie70Dart
- Start date
-
I ran a 741 3.55 Sure Grip from Randys Ring and Pinion for ten years. We made hundreds of passes with about 440 HP. On MT ET Streets, I would dump the clutch at 4000 RPM in a 3700 pound car. You will have a hard time breaking it. Now what kind of shape the gears and bearings are in on the unit you are looking at is unknown, but for $50 its worth trying.
tekslk
Well-Known Member
being a open rear you cant hurt it.
abodyjoe
Well-Known Member
Ran my dart a lot with a 741 case and 3:91 gear. Used Hoosier tires and would pull the left front tire a inch or two and never hurt the rear.
Also ran a 741 case in my 64 440 valiant with no issues.
If the gears are in good shape and set up properly then I think you'll be fine
Also ran a 741 case in my 64 440 valiant with no issues.
If the gears are in good shape and set up properly then I think you'll be fine
Ok, thanks for the replies. I picked up a B-body housing and axles for what I thought was a good price, $100. It looks like the case can take either the clutch or cone sure grip. At least I'm hoping.
abodyjoe
Well-Known Member
Sure grip units will fit any case. Some cases will use a different bearing though. Not a big deal
I ran a stock 340 with a 741 case 3.55 ratio rear for decades. when new, the car ran 13.5 @ 105 with sticky H70x14's. I had over 350 runs on that combo and still have the same rear end 43 years later. So, I guess it is strong enough for a 340.
Bob
Bob
1970Duster
Well-Known Member
- Joined
- May 30, 2010
- Messages
- 6,644
- Reaction score
- 215
I run/use 489s with solid pinion sleeves only, and have never had a problem.
Just got back. There was a 69 Dart GT in the garage. Looking good. It is the dad of who I got the case from. I mentioned about getting a 8 3/4 housing and piecing the rear end together, since I can't afford the $1500 for a rear end. Then said something about backing plates and was told the old man has upgraded to discs on the rear and now had no use for the old backing plates. Picked up the plates with NEW brake hardware, no drums, for $20. Need cleaning. Good shape. Fit the housing I have, and the axles I have fit the 741. So, for $70 I got the housing and backing plates with the brakes. All in all I can't complain. Thanks for the responses.
Graminizer
The "Big G"
Nice score! I picked up an open 489 with 3.23's for $35 a few weeks ago.....I couldn't leave without that one! I had a 741 first, but the 489 will be replacing it shortly.:burnout:
Excellent! Nice price and you got the good pinion.
There is nothing wrong with a 741 case other than lack of desirable gear sets new. I've run mine 5 years with a set of used 4.88's in my 65 Barracuda; best time of 11.14 at 108mph, 28x9 Hooser slicks.
I've never quite understood why many people, and the after market bypass the unit. When an 8 3/4 gives up, it usually shells teeth off the ring gear. Also, all three units use the same yoke, so.............................?
I've never quite understood why many people, and the after market bypass the unit. When an 8 3/4 gives up, it usually shells teeth off the ring gear. Also, all three units use the same yoke, so.............................?
................good score........except u cant use A body 8.75 backing plates with B body housing and axles.....they each hace specific offsets.....the pumpkins all interchange......my old duster has a 741 case with 4.10s in it for the lsat 30 years ...runs 11.001 with a 1.34 60 ft...on 12.2x31.25 slicks......kim.........
Thanks oldkimmer, but how can I tell? I was able to slide these plates onto the housing all the way. There is a "flat" spot cutout I had to line up first. Does that mean these will work then? Thanks!
Of the backing plates you just got: what is the drum diameter and what is the shoe width?
"A" body 8 3/4 drums and shoes are 10 inches dia and 1 3/4 inches wide; "B", "C", "E" body drums and shoes are 10 or 11 inch dia, 2 to 2 1/2 inches wide depending on option statious.
"A" body axels are approximatly 1/4 inch shorter from the bearing to the wheel flange than "B, "C", "E" axels and this difference is also reflected in the backing plates. Stock axels all have the same spline count, so the fact that the axels you just got slide into your 741 carrier is/was to be expected. BTW is the thrust button still in the carrier?
To see if/how this will work take the following measurements:
Housing width, flange to flange
axel length, outside flange to end
This info will tell what you have and what your options are.
Ok, brakes dia is 10 in, shoe width is 1 3/4. Perch to perch is 44 in., flange to flange is 54 in. Didn't do the back of axle to bearing. I took the time to put one plate with the axle on. Just for the giggles. It looks to be BBP axles. See pics. Thanks!
Since I am able to bolt the plates up like that, does that mean I can use them? Thanks.
44 inch perches are B body width.
Isn't a B rear that comes in at 54", there is one that's 54.25 and another that's ~55"
Isn't a B rear that comes in at 54", there is one that's 54.25 and another that's ~55"
Ok, thanks to all for the information. I don't know a whole lot about rearends. I definitely know more now. It seems either I change axles to sbp, or change backing plates to the larger size, thats 11in x 2.5 shoes. I'm only out the $18 I paid for the smaller plates. Inexpensive lesson. I may end up selling the smaller plates for what I paid. I'll have to wait and see. Again, thanks to all for the info and the patience.
-
