Which rear 8.25 or 8.75 swap for new project

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gliderider06

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I acquired a Duster last month and it has an 8.25 rear in it already w/LBP. I will be running an aluminum headed 318 Magnum that made little over 400 Hp on the Dyno and will run a727 w/ a Transgo kit in it. I plan on 3.91 gears and already have a set for the 8.25. I'll need a suregrip unit. I have an opportunity to get a 68 B body 8.75 rear complete for 300.00, but I will still need gears, SG etc to convert it. Either rear I use, I will need to move the pearches since I have the isolator mounts on the current rear. What are your thoughts? My last car I ran an 8.25 with no problems, but it made less power. I'm just not sure if I should get the 8.75 or spend the money elsewhere.
 
Having everything you need for the 8.25 is nice. It's a decent rear end. But the ability to swap cases, availability of parts, strength of the 8.75, etc etc. Wins out in the end. Want highway gears? Swap out the center section the morning before your cruise. Putting more power in your engine? Good thing you got that 8.75.

In the end. Guys ALWAYS go 8.75. Eventually you just need it. And one day you will to. Why do it later when it'll cost even more (prices on that stuff is getting outrageous in my opinion) when you can do it now.
 
I acquired a Duster last month and it has an 8.25 rear in it already w/LBP. I will be running an aluminum headed 318 Magnum that made little over 400 Hp on the Dyno and will run a727 w/ a Transgo kit in it. I plan on 3.91 gears and already have a set for the 8.25. I'll need a suregrip unit. I have an opportunity to get a 68 B body 8.75 rear complete for 300.00, but I will still need gears, SG etc to convert it. Either rear I use, I will need to move the pearches since I have the isolator mounts on the current rear. What are your thoughts? My last car I ran an 8.25 with no problems, but it made less power. I'm just not sure if I should get the 8.75 or spend the money elsewhere.

Hi Gliderider! You answered your own question when you said your over 400hp...and you'll go more. You also said you have already located an 83/4. I also run a late 60's BB 83/4 '489'489 in my DART for year's and Love It!. There are 3 different cases/carrier's and multiple opinion's, so at the end of this-I will include the information(one of many sources)that can help you . One the lighter end you have the '741' which is a low horse/low torque option with a . ..1-3/8" pinion assembly and then the larger '742' with a .. 1-3/4" pinion. The beefiest is the '489'. with the Big pinion shaft at 17/8". To me, the 489 case is just the cream of all creamer's-all american and no artificle additives! One thing is for sure. If your 400 +, you will want at least a '742'. I went with 489 so I could just keep adding horsepower and just change gear's and carrier's. I would stay away from the 741. That's just my opinion. However it goes, I wish you much success and fun. Post on TheDoDgELoDgE.CoM... page of facebook when your done! 'Look forward to it. Following is that link. Hope it help's you. -->> Everything You Ever Wanted To Know About The 8 3/4 Axle If you need a physical Guru to speak with or work from, try Paul Bassett Owner/Operator of PB Performance, Salisberry,NC.. He ran Strange for numerous year's and is the reason the Dana rear work's as well as it does -->> PB-Performance Gears and Services ,SALISBURY NC! Good Luck Moparian
 
As long as your not beating the crap out of the 8-1/4, it will last with over 400hp. If equipped with slicks and the car is heavy, you can expect a shortened life.

If you have street tires and cruise the Blvd. you should be just fine. You can save a lot of money if you wait on the installation. At the price offer d for the 8-3/4, I would certainly pick it up.
 
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