1971 rearend 741 case questions

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Penstarpurist

Penstarpurist

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My son bought a 1971 dodge dart for the 8 3/4 it has. We got it pulled out and see it's a 741 case with 2.76 years in it. He is putting it in his 1971 Plymouth valiant, which is a 318 car, 904 trans and currently a 7.25. I know we need to use the driveline from the dart as the difference in wheelbase. The dart is a 318/904 as well. Car is rusted beyond any reasonable repair. My question is this, my son was wanting to put 3.23 years in the 741 case? But I'm finding out that no one in the aftermath world makes a set of 3.23 gears for a 741 case. His car currently has 2.76 gears in the 7.25, so it's not like he cant live with it. I spoke with Strange, they said nope. Nothing for the 741, Dr. Diff said he has 3.55 and 3.91. But have to upgrade our pinion to a 29 spline from the stock 10 spline. Total cost for gears, bearings, spline around $340.00 not horrible at all. He did say that he is making 3.23 for the Dana 60 and is heavily debating adding that gearset ro his 741 line up. What are my options? Beyond buying a 742 or 489 case. Did Chrysler make a 3.23 in a 741 ever? Do they come up for sale?
 
3:55 are a highly versatile street gear.

Gearsets avail from factory
Part II, Appendix C: OE Ring and Pinion Sets
Tooth Count Ratio Carriers
41-14 2.93 '448', '657', '741', '742', '489'
41-13 3.15 '448', '657', '985',
35-11 3.19 '448', '657'
3.23 '741', '742', '489'
43-13 3.31 '448' (57-61), '741' (62-63)
37-11 3.36 '448', '657'
39-11 3.55 '448', '657', '741', '742', '489'
41-11 3.73 '448', '657', '985', '741'
43-11 3.91 '448', '657'
 
Wait? No 2.76? I thought for sure there was a 2.76 ratio. That's what we have in this one. Maybe it's not original set to the car.
 
Yes Mopar made 2.76 and 2.94. I guess they were left of the list because of undesirability.
 
SGBARRACUDA said:
Yes Mopar made 2.76 and 2.94. I guess they were left of the list because of undesirability.
Click to expand...
I know I wouldn't pay money for a set of 2.76 gears. Oh wait. I bought my son the valiant with the 2.76 gearset. I guess I would pay money for them. Lol. Do you think I should look for a set of factory 3.23's in a ten spline or look for a 489 3rd member then buy a new set of 29 spline 3.23's from Dr. Diff. ?Strange said the 1971 741 case is "a rare bird". Not sure why, I've seen many 741 for sale. I think the best option is to install the rearend as geared after a quick brake rebuild, and hoses. Then wait for Dr. Diff to add the 3.23 to his 741 line up. And keep an eye out for decent priced 742/489 3rd members to buy up.
 
I would think that a used set of 3.23 gears for a 741 housing should be as common as dirt....careful shopping should get you a nice set
 
Yeah, I'm going to check the forum for sale page daily until I find a good used set.
 
Well if it were me? I would install the 8 3/4 as is and get all the assoc. parts then look for a good 3.23 SG third member. You will also need to shorten the drive shaft.
741's are plenty tough enough to handle what you have.
 
Penstarpurist said:
I know I wouldn't pay money for a set of 2.76 gears. Oh wait. I bought my son the valiant with the 2.76 gearset. I guess I would pay money for them. Lol. Do you think I should look for a set of factory 3.23's in a ten spline or look for a 489 3rd member then buy a new set of 29 spline 3.23's from Dr. Diff. ?Strange said the 1971 741 case is "a rare bird". Not sure why, I've seen many 741 for sale. I think the best option is to install the rearend as geared after a quick brake rebuild, and hoses. Then wait for Dr. Diff to add the 3.23 to his 741 line up. And keep an eye out for decent priced 742/489 3rd members to buy up.
Click to expand...
I recently bought a 741 case 3.23 gears open carrier fine spline pinion from a member here for like $125 I believe. just keep an eye open, just put them in my van 2 days ago
 
Just buy an extra third member with the gears you want, they all interchange in the housing, unless you get into some aftermarket stuff with different splined axles.
 
I agree. I am definitely looking for an extra 3rd member. It bums me out when I think of how many 3rd members I used to have. Got tired of lugging them around everytime I moved. Paid alot less back then for sure.
 
That's my plan, 67 has 741 case 323 gears. 69 cuda 489 case 323 gears. I need something other than 323 lol.
I dont think that 741 case is original to your car. 489 was in production in 69.
 
^^^
sireland67 said:
Just buy an extra third member with the gears you want, they all interchange in the housing, unless you get into some aftermarket stuff with different splined axles.
Click to expand...

Penstarpurist said:
I agree. I am definitely looking for an extra 3rd member. It bums me out when I think of how many 3rd members I used to have. Got tired of lugging them around everytime I moved. Paid alot less back then for sure.
Click to expand...
 
Still have the nice OEM 3.55 ring and pinion out of my 741, had it listed a few times here. Only ones who were interested immediately lost interest when I wouldn't give it to them for free. :rolleyes:
 
I tried to talk my son into going with 3.55's but he has himself convinced that he wants to go with 3.23. Even though my buddy with a demon has said many times that he wished he would have put 3.55 in and not the top tall 3.23. Dr. Diff sells new 3.55 and 3.91 sets for the 741.
 
I like that price for sure. Not sure what shipping from Kansas to Oregon on a complete 3rd member would be. Of course even if it cost the same as the case it may well be worth it. I may have to give it a call and see if he is down with shipping. Though the six states driveline shop charges pretty steep prices here. They are the best there is, they have built many driveline for me.
 
I picked this one up for $50.00, so keep your eyes peeled.

323 ad for 50 bucks.JPG
 
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