Jul 7, 2024
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Hi there,

I got a 79 Regal, swapped the 305 for a 350 with some speedparts, im trying to build a drift car on the cheap, the 350 got the juice for it but the rear end is holding it back, i think its a 2.30 or something like that, im looking to put like 3.73 gears in it but i need a second rear end to work on(wanna rebuild it) if thats even necessary? Can i just put other gears in it and leave the rest alone? And i found a 79 Malibu rear end, is that gonna fit? Do i have to change anything? I have seen a thread about G body rear ends but didnt see anything that could help me. Both rear ends are 7.5 inch 10 bolts. Im in the EU NL, stuff is hard to find out here, this 79 Malibu rear might be the only option.
 

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Hi there,

I got a 79 Regal, swapped the 305 for a 350 with some speedparts, im trying to build a drift car on the cheap, the 350 got the juice for it but the rear end is holding it back, i think its a 2.30 or something like that, im looking to put like 3.73 gears in it but i need a second rear end to work on(wanna rebuild it) if thats even necessary? Can i just put other gears in it and leave the rest alone? And i found a 79 Malibu rear end, is that gonna fit? Do i have to change anything? I have seen a thread about G body rear ends but didnt see anything that could help me. Both rear ends are 7.5 inch 10 bolts. Im in the EU NL, stuff is hard to find out here, this 79 Malibu rear might be the only option.
Yes, the rear ends are interchangeable as they are the same rear ends. Any '78-'88 G will share the same rear end.
 
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Yeah, you can build the 'Bu rear end but it will cost you some $$ as about all you will starting with will be the housing. The diff can be had from Yukon Gear or Eaton, the axles Moser? All the build bits, bearings, spacers, shims, etc., can be obtained as a kit. Also time to consider what version of rear brakes you want, drum or disk and price that out (more $$)

Once you get an all in cost for the parts to do the rear end build, you might then want to check out ready to run units. There are several advertisers on this board who offer complete ready to use rear end systems. The reason that I suggest this option is that, for what you want, it might be cheaper for you to acquire a pre-built unit that has the features you need already matched for compatibility and then assembled and tested.

The other point to consider in this exercise is that the 7.5 x 10 bolt has a practical upper limit when it comes to tolerating horsepower insults. There are a fair amount of upgrades that the 7.5 case can accept but at some point the case itself becomes the weak link and, subject to input from others on this board, I believe that there is an upper limit on the size of gear/differential that the housing will accept.

If your objective is to drift your ride as you say, then you are probably going to be subjecting your rear end to wicked amounts of torque while getting the whip to slide and shuffle, so not only is the rear end going to get beaten on, so will the suspension. Might be time to check out E-Bay and the other vendor outlets and see what is being offered by way of drifter parts that would work for you.



Nick
 
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Yeah, you can build the 'Bu rear end but it will cost you some $$ as about all you will starting with will be the housing. The diff can be had from Yukon Gear or Eaton, the axles Moser? All the build bits, bearings, spacers, shims, etc., can be obtained as a kit. Also time to consider what version of rear brakes you want, drum or disk and price that out (more $$)

Once you get an all in cost for the parts to do the rear end build, you might then want to check out ready to run units. There are several advertisers on this board who offer complete ready to use rear end systems. The reason that I suggest this option is that, for what you want, it might be cheaper for you to acquire a pre-built unit that has the features you need already matched for compatibility and then assembled and tested.

The other point to consider in this exercise is that the 7.5 x 10 bolt has a practical upper limit when it comes to tolerating horsepower insults. There are a fair amount of upgrades that the 7.5 case can accept but at some point the case itself becomes the weak link and, subject to input from others on this board, I believe that there is an upper limit on the size of gear/differential that the housing will accept.

If your objective is to drift your ride as you say, then you are probably going to be subjecting your rear end to wicked amounts of torque while getting the whip to slide and shuffle, so not only is the rear end going to get beaten on, so will the suspension. Might be time to check out E-Bay and the other vendor outlets and see what is being offered by way of drifter parts that would work for you.



Nick
I fully agree on that! Im also thinking about a ford 9inch, i know a place that could make that work but indeed i have to consider alot of things, i could get a 9inch for like 2/300 and it would need another idk 2k to get it to where i want, i think it would be around 1500 for the 10bolt if i let them do the work, so depending on what i want, i guess i could either save 500 or just go all out and have an unbreakable 9inch with disk brakes.. Oh and i can get this 10 bolt Malibu rear for 50 bucks but the diff exploded.. he says it should be rebuildable..
 
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Food for thought: big difference between estimates and final bills, extra damage or things take longer/need extra parts/fabrication it wont come out of the shop profit. It's easy to spend someone else's money, for sure. But given your intended use, I'd err towards strength. This isn't going to be a gently driven car from the sounds of it. The 9" or other upgrade equivalent will add more than $500 in resale value to the car over any 10 bolt.

The only thing I'd suggest, and, availability in your area is different than ours: there's companies building all-new purpose built rear ends, 9 inch and otherwise, that are drop in ready. No junkyard blown up patch together and fabricate in your shop. You open the crate, it's all new,.and you install. You get 100% new parts, spec. to.order for brakes, gear ratios, spline count etc. Just throw it in, bleed, and drive.

It's piece of mind,.cost certainty, and warranty at a cost.
 
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A rear carrier gear change is not for the rookie or faint-of-heart. Lots of expensive parts, lots of expensive tools that are needed, PLENTY of patience. Grab a factory manual and read the part about the gears. If you don't get a headache- carry on. I build rears with a GM stealership pinion depth tool kit, and it took me a LONG time to learn to do it right. You can't just swap parts and expect success. Shops that even know how to do it charge a bundle.

That said, a lot of Monte Carlo SS cars came with 3:73 non-posi rears. They will bolt right in. If you can grab one cheaply, use it until you break it. Later, if this is still your plan, then go for the big bucks heavy duty rear. As stated above- it will pay in the long run to get the best you can afford.
 
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Can't be a lot of choices out there in the Netherlands. You'd have half a dozen solid options in USA for $2-3k.
 
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If you're considering sticking with a 7.5, keep in mind that the lug nuts change from SAE to metric between '80 and '81. If drifting is your end goal in mind, my thoughts is the 7.5 might not be strong enough for that intent and purpose but what do I know...I've never built a drift car before.
 
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If you're considering sticking with a 7.5, keep in mind that the lug nuts change from SAE to metric between '80 and '81. If drifting is your end goal in mind, my thoughts is the 7.5 might not be strong enough for that intent and purpose but what do I know...I've never built a drift car before.
78-81 7/16-20 SAE
82+ 12x1.50 Metric
As delivered from GM
 
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