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8 3/4 and high hp
ok I'm planning a big 440 build up involving e-heads, roller cam, etc. I'm wondering how the 8 3/4 will like it. I've always read/heard that it really comes down to ring gear size. More or less that you can put all the best axles, bearings gears whatever in and the weak link is the size of the gear- it just doesn't have enough meat to stand big hp, hence the need for the Dana and it's 9 3/4 ring.
I've got a 3.91 gear, install kit, and an Auburn diff in the garage. I'm wanting to know if I spend the 580 bucks Earnhardt's wants for an aluminum carrier if it would be flushing the cash. I need a carrier as the ones I have are already setup the way I want. My only extra was given to me by a freind but I'm not sure if the caps are a matched set or not. I'm afraid that I'll get my new parts in there and the caps will be off a tiny amount and the death of my parts will follow.
I may not have worded this post very well or made it easy to understand so I'll check in often. At least it's a start for discussion.
The 8 3/4 is a good rear end.Sometime in I belive 1974,Chrysler changed the main caps.The good caps have a "circle" where the adjuster lock bolt goes,and the later caps which are not as strong have a square pad.The obvious thing to do is install the main caps from Mark Williams,use a Dana sure grip,and set the rear up correctly.We used to run 8 3/4's at the drag strip,but when even getting the whole 3rd member from Mopar,we would tear them up too.We ended up going with Dana 60's in both cars,and never had a problem since.The 8 3/4 can live,but with a Auburn sure grip, a 4-speed, and slicks it will be tough.
Re: 8 3/4 and high hp
all the 8 3/4 needs for strength is to be braced,it'll rarely break if the banjo can't flex(that's it's weak link,not it's ring gear,especially a 489),moser axles and off you go, if racing the 60 will plant better,it's only 50lbs heavier(alot of people think it's alot more),but the ratchet type diff makes it run straiter,whereas the suregrip clutches will "fishtail" for awhile before hooking up,but the 8 3/4 will catch the dana and then some after the 60 foot point,they both have their pros and cons,for street go 8 3/4 ,for a track car dana ,it will take much more abuse in the long run,the mopar will be quieter on the street and won't give you the ol' popping around the corners noise.
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