8.8 specs for a 79 Monte
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an 8.2 out of a chevelle would also work, it'd be easily strong enough for the engine and relatively cheap compared to what 9" and 12 bolts go for
79CMC said:
nah i understand that. the 7.5 are junk to do anything with. not worth the time or money. while they will hold up its sort of pointless.
the good thing about the 8.5 is that they hold their value. I bought mine complete for $900 with driveshaft. I could turn it for $1100 with the girddle i threw on it.
Honestly you have to look at what your going to do with the car.
in my case im going to a 9 inch becuase of the center section. I plan on spraying it and will need to change the gearing and converter. and Ill be putting out some killer power so its needed.
Right now its a streetable car. the 8.5 is great. some launches nothing crazy
but you got to ask yourself what are your plans and if you are going to ever sell the car. IMO people that look at a gbody are impressed if it has a 8.5 or a 9" and youll make your money back. Ive never seen of the 8.8 conversion and i would actually shy away from it if i were buying a car with it becuase its not that common.
Let us know how it goes. im interested in.
78MC-I've heard the same thing about the explorers. I'll have to research to check the width and see if it'll fit with little fab work.
JBreu-I just found that link last night as well-Maliburacing is blocked on government computers until late at night. I guess they figure if I'm looking up something with "racing" in the site name, I'm not fighting the Taliban. I've seen a few dudes on MR that like/have done the swap. But the whole blocked thing kind of restricts my forum posting/searching.
pontiacgp-I'll keep the 8.2 in mind. Haven't heard much about it, either.
GRK-You're right about figuring out the car's purpose. Right now, it's a daily driver with zero track time (and that's my intent for awhilie). I might drop a mild cam in there if I get bored. I was tempted to upgrade the 7.5 and risk it, but economically it didn't make sense. And the 8.5 is expensive and rare, so I figured the 8.8 would be a good compromise if not too much trouble. That's part of the challenge anyways. The fact that TRZ and baseline made a kit is a good sign; I figured there'd be more cars with them. I don't plan on ever selling this car because I'll never make my money back-I rue the day when someone T-bones me and I get $1500 in insurance money. If I stumble upon an 8.5 fair deal (I'm still actively searching), I will certainly snatch it up. But the 8.8 is my more realistic back-up plan. If/when I make this happen (I get back from Afghanistan Feb/March), I'll be sure to come back and let ya'll know how it goes.
JBreu-I just found that link last night as well-Maliburacing is blocked on government computers until late at night. I guess they figure if I'm looking up something with "racing" in the site name, I'm not fighting the Taliban. I've seen a few dudes on MR that like/have done the swap. But the whole blocked thing kind of restricts my forum posting/searching.
pontiacgp-I'll keep the 8.2 in mind. Haven't heard much about it, either.
GRK-You're right about figuring out the car's purpose. Right now, it's a daily driver with zero track time (and that's my intent for awhilie). I might drop a mild cam in there if I get bored. I was tempted to upgrade the 7.5 and risk it, but economically it didn't make sense. And the 8.5 is expensive and rare, so I figured the 8.8 would be a good compromise if not too much trouble. That's part of the challenge anyways. The fact that TRZ and baseline made a kit is a good sign; I figured there'd be more cars with them. I don't plan on ever selling this car because I'll never make my money back-I rue the day when someone T-bones me and I get $1500 in insurance money. If I stumble upon an 8.5 fair deal (I'm still actively searching), I will certainly snatch it up. But the 8.8 is my more realistic back-up plan. If/when I make this happen (I get back from Afghanistan Feb/March), I'll be sure to come back and let ya'll know how it goes.
I picked up a complete 8.2 for $600, it had an Easton posi with 3.08 gears. I just changed the pinion thrust washers, axle bearing and seals and installed it with the help of JBrue's tips. Depending on what you read the 8.2 are good for 500 hp with upgraded axles
how does upgrading a 7.5 not make sense? the only reason you hear about them breaking all the time is because people just throw posi's or spools in them without making any other upgrades then cry about it when they grenade. If your not doing any major drag racing or constantly beating on it and throwing slicks on then its more than enough especially with just a stock ls1... honestly i would take a completely rebuilt and upgraded 7.5 over a used unknown condition 8.5 (that both would cost about the same) anyday.
how do you upgrade the 7.5?
1) weld the axle tubes all the way around the housing, there only spot welded from factory
2)get a quality 28 Spline differential carrier (eaton,auburn, etc) and gear set of your choice (GM, richmound, strange, etc) and 28 spline Grand national replacement axles or for more protection get alloy Grand national axles which are even stronger
3)Get an aluminum rear end girdle that has main cap supports which makes the housing more rigid helps keep everything in place
4)get a zytanium cross pin because stocks are known to break, and a soilid bearing spacer instead of a crush sleeve to prevent the gears from walking
and 5) finally use good gear oil like the Redline Synthetic Shockproof gear oil and friction modifier
To me its money well spent and you end up with a brand new rear and peace of mind, what more could you want
how do you upgrade the 7.5?
1) weld the axle tubes all the way around the housing, there only spot welded from factory
2)get a quality 28 Spline differential carrier (eaton,auburn, etc) and gear set of your choice (GM, richmound, strange, etc) and 28 spline Grand national replacement axles or for more protection get alloy Grand national axles which are even stronger
3)Get an aluminum rear end girdle that has main cap supports which makes the housing more rigid helps keep everything in place
4)get a zytanium cross pin because stocks are known to break, and a soilid bearing spacer instead of a crush sleeve to prevent the gears from walking
and 5) finally use good gear oil like the Redline Synthetic Shockproof gear oil and friction modifier
To me its money well spent and you end up with a brand new rear and peace of mind, what more could you want
richp85elco...I have nothing against 7.5's but how much is that upgrade going to cost him?....I bet more than what it cost me for my 8.2 and I can sell my 8.2 for the price I paid, if not more.
You will want to look for one out a fox body mustang, they are the closest to stock width. The sn95's will work but are a little wider. Explorer rears are only good for parts, the housings don't have the ears. The fox rears will be 28 spline while the explorer is 31. There is something about using 2 left axles from a 31 spline ranger rear to make the 31 spline carrier work in the fox housinf for a cheap upgrade, but i'm not 100% on the specifics anymore.
As far as cost for strenght goes the 8.8 looks hard to beat. You can get a decent geared limited slip 8.8 for 100-300 easy. Then I've heard of one member using the stock fox upper arms and the stock g body lower arms and bolting it in. You can also use the yoke from the explorer and just get a different u-joint to make it work. This doesn't help the instant center issue but it gets you started for a small investment.
There is a real good chance i'll be doing this and when I do it will be in my build thread.
As far as cost for strenght goes the 8.8 looks hard to beat. You can get a decent geared limited slip 8.8 for 100-300 easy. Then I've heard of one member using the stock fox upper arms and the stock g body lower arms and bolting it in. You can also use the yoke from the explorer and just get a different u-joint to make it work. This doesn't help the instant center issue but it gets you started for a small investment.
There is a real good chance i'll be doing this and when I do it will be in my build thread.
about the same as an 8.5 for all new stuff, and all above can be done cheaply as well you can grab a 28 spline diff an gear set from fbodies 7.625 rear firebirds, camaros etc for very cheap at a junkyard, stock GN axles come up all the time when people upgrade to aftermarket or even new for stock replacements are cheap, . And thats the grunt of the cost if you buy new,this in itself is much stronger than the 26 spline units the next most expensive item is the diff cover at $130 which you should get if beefing up any rear end. And no fabrication or guess work, replacing u joints brakes, drilling for different wheel patterns or limiting your self to ford wheels
richp-I completely agree with you when you say you know what you're getting when you rebuild a 7.5 for the same price as a shot-in-the-dark 8.5. That's why I was originally tempted to rebuild my current rear, especially since my LS1 isn't going to be a beast; thanks for the rebuild run-down. However, you said the used 8.5 and a rebuilt 7.5 would be close to the same price. By the same token, for close to or less than that price, albeit with slightly more guess work, I'd have an 8.8. To me, it's a good compromise in the long run, especially if I win the lottery and decide to go crazy with HP upgrades. While I have no intentions of doing that right now, a 7.5 would nonetheless limit my options. Plus, it sounds like an interesting challenge.
jrm-Awesome info. I was talking to one of my Marines that's got a few fox bodies and a lightning and that was his recommendation as well. I will admit, his expertise with Fords is definitely a factor for me in this swap. I know he'll be able to help me out on sourcing and rebuilding a rear if necessary. I'll probably use the baseline kit for the control arms, since I'm upgrading the suspension anyways, so it's almost a sunk cost. Any idea when you're planning on doing the swap?
jrm-Awesome info. I was talking to one of my Marines that's got a few fox bodies and a lightning and that was his recommendation as well. I will admit, his expertise with Fords is definitely a factor for me in this swap. I know he'll be able to help me out on sourcing and rebuilding a rear if necessary. I'll probably use the baseline kit for the control arms, since I'm upgrading the suspension anyways, so it's almost a sunk cost. Any idea when you're planning on doing the swap?
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