stony Posted December 2, 2001 Share Posted December 2, 2001 found one on ebay. My question is a rear end is a rear end when it comes to replaceing the IRS? IS the mopar rear end any good? its the 8 3/4 5 on 4.5 lug drum setup with posi. would i just measure it up and weld on the mounts? or would there be anything special because its a mopar. thanks shipping will prabably nix the deal but cant hurt to get all the info i can get ;> Quote Link to comment Share on other sites More sharing options...
Guest super280z Posted December 2, 2001 Share Posted December 2, 2001 Stony, the mopar 8 -3/4 is a very stout unit that i have had in mind for quite a while. the plus sides to using this rear include the fact that it does not use c-clips and parts are very readily avaliable. the removable center section makes gear changes a snap. it's very similar to the ford 9 but mopar version for those of us that just wont stand to have anything fomoco in our rides . keep us informed if this is what you end up going with because i'm eventually going to do this one as well. Quote Link to comment Share on other sites More sharing options...
stony Posted December 2, 2001 Author Share Posted December 2, 2001 So as far as rear ends go it wouldnt be any different then insalling a 9 inch or 12 bolt as far as mounting hardware and bracketry?<< Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 2, 2001 Share Posted December 2, 2001 Its a good rearend I believe Dana makes them. Lug pattern should be the same as Ford. (and AMC just for trivia ). Gearing I'm not sure, I can't recall they're ratios, but know they made a 3.23 ratio which would be a little higher than most of the nissan ones. I'm sure ratio's are not a problem though, there are many ring gears for it. Mounting shouldn't be any different than any four link setup or what your going to use, its a straight axle just like the rest. Pictures please if you do it. Regards, Lone Quote Link to comment Share on other sites More sharing options...
stony Posted December 2, 2001 Author Share Posted December 2, 2001 ok hes telling me its 39 inches drum to drum that is almost perfect ;> should be able to get some big meats under the fenders without too much cutting. i think the ss bar setup MIKEKZ is using on his green and black z is gonna work good ;> Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 2, 2001 Share Posted December 2, 2001 do you know what the rear end gear ratio is? i used to own a 74 charger SE. the best car i ever bought. purchased it for 200 and ended up selling it for 600 and a motorcycle. never gave me anyproblems over than rings were starting to go (300,000+ miles with no rebuild!) and the ocasional vaporlock on a hot day. that car is what started my nickname as freak in this town . i made a highschool girl cry and after that experiance i never had any problems with any body not wanting to buckle up for the ride...heh heh heh anyways i was just curious since i know a lot of the late seventies into late eighties came with a fairly high 2.73 ratio (like mine) i always wondered how much of a differance a 3.90 ratio would have made. with small it is did it come off a dart? or was it shortened? just kind of curious. should make for a nice swap though. if they can handle a hopped up hemi, i don't think you'll have any problems with broken parts. good luck Quote Link to comment Share on other sites More sharing options...
stony Posted December 3, 2001 Author Share Posted December 3, 2001 its a 3.23 which of course is no good for me ill be changing that out with something higher like a 4.11 or something like that Quote Link to comment Share on other sites More sharing options...
Mike kZ Posted December 3, 2001 Share Posted December 3, 2001 Stony, I would measure, or mock up something under your car to see what size tire/wheel combo would fit with a 39" drum to drum diff. My diff came out to around 45" and my tire print is around 15" wide. So with a 6" narrower diff you could put prostreet tires under there, but they don't make those in radials. Quote Link to comment Share on other sites More sharing options...
stony Posted December 4, 2001 Author Share Posted December 4, 2001 thats the plan. It eill require bigger wheel tubs but well see. i havent met the reserve yet and its getting kinda high for me now soprabably wont ;< Quote Link to comment Share on other sites More sharing options...
Guest John Adkins Posted December 4, 2001 Share Posted December 4, 2001 The nice thing about the 8 3/4 is that it is just like a Ford 9 inch in that there are lots of aftermarket gearsets available in a lot of ratios. Quite a few LSD units are available too. The center section drops out of the front of the housing just a like a Ford 9" too, which makes it easy to change gears.... As far as I know the narrowest stock 8 3/4 was the early a-body and is about 54" wide.... So the 39" rearend must be narrowed... Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 8, 2001 Share Posted December 8, 2001 If you can make it fit the Mopar 8 3/4" rear is a very nice piece. It has no problem standing up to 500hp, 500+lb. ft. big block engines through automatic transmissions in 3600+lb cars. We Mopar guys stick with it unless we are running a very stout big block and a 4 speed with traction, then we go with a Dana 60. Oh, by the way, 8 3/4's are fairly common. You can find them in cars, trucks, and vans. I wouldn't pay too much for one on ebay. There is probably a nice one in a junkyard near you, with a Sure Grip and a gear ratio from 2.76 to 4.10. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 8, 2001 Share Posted December 8, 2001 has mopar ever made any IRS diffs? kinda like ford did with the 8.8 diff? i figure if i ever have to upgrade my rearend it would be nice to make it a mopar unit but i also want to keep it a indapendent setup back there. anybody know of any conversion kits for the 8 3/4 diff to make them a IRS? Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 8, 2001 Share Posted December 8, 2001 Well, there is the Viper. ChaaaChing $$$$$$$. And I believe the prowler, but that had the tranny back there to (transaxle, think new vette like). Those are the only ones I can think of outside of maybe the front end of a later Jeep. Regards, Lone Quote Link to comment Share on other sites More sharing options...
Guest John Adkins Posted December 8, 2001 Share Posted December 8, 2001 I believe the Viper rearend is a Dana 44.... Didn't Corvettes use a Dana 44 for a while too? The viper trans is a beefed up version of the T56.... hmm... seems like GM and Chrysler use a lot of the same drivetrain component suppliers... Quote Link to comment Share on other sites More sharing options...
stony Posted December 9, 2001 Author Share Posted December 9, 2001 ouch!!! quoting 550 (includes shipping to alaska) for a 39 inch drum to drum 8 3/4 rear end minus the differential!!! Im thinking i could get one from a junk yard and have it narrowed to exactly what i need for less then that? are the mopar axle 8 3/4 tapered or non tapered? can i just cut and respline a set or would i need special axles made for the 8 3/4 rear end? Quote Link to comment Share on other sites More sharing options...
Mike kZ Posted December 10, 2001 Share Posted December 10, 2001 Have custom axles made, they are stronger, and thicker. If you have stock axles cut and resplinded, they're not as strong because they weren't heat treated after the cut, and I'm not sure you can heat treat after without the axle becoming brittle. Quote Link to comment Share on other sites More sharing options...
stony Posted December 12, 2001 Author Share Posted December 12, 2001 oh well didnt win the mopar rearend got too high for me.....did win a ford 9 inch narrowed to 34 inches with moser 35 spline axles complete with retainers and bearings.. all i need is a brake setup and a spool ;> Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 12, 2001 Share Posted December 12, 2001 hey good for you stony that sounds like its a pretty nice setup. should work out great. i just gotta ask, so how many ponies are you putting down now? is the RB26dett (its a dett right?) still stock or have you been playing with it. Quote Link to comment Share on other sites More sharing options...
stony Posted December 12, 2001 Author Share Posted December 12, 2001 no dyno nymbers yet it ran 11.1 at 121mph with lots of wheelspin in first and second. i have a aftermarket trust intercooler, and sds, other then that its bone stock , stock booste and everything ;> Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 19, 2001 Share Posted December 19, 2001 I run an 8 3/4" 4:88 with 30" tall tire with a six speed. There are several carriers three I believe one of the three isn't advisable to use, some one correct me if I'm wrong, But I think there is a #789 and a #742 and these are the ones to have and one of these has a larger dia. pinion shaft. I have the better of the two but I'm not crawling under there to look. I know my axels are tapered and fat like baseball bats. It's a very stout piece as I have side stepped the clutch at 5000 RPMS and twisted a drive shaft into a pretzel replaced it and no harm done to the third member. I believe my vehicle weighed (with me in it) 3875 lb.s at the time. I think they are just as good as any Ford 9". Quote Link to comment Share on other sites More sharing options...
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