ZR2 8.5 INSTALL
#1
ZR2 8.5 INSTALL
I am building a 83Z into a trackday car and wanted better rear axle with all the goodies. I already had plans to make the rear suspension a 3 link so the torq arm was not a factor. I settled on an 8.5 (actually an 8.625) rear axle from a 1999 ZR2 Blazer as it was the best bang for the buck. These axle assemblies are 1 1/2 inches wider than a 3rd gen and only came with 30 spline axles, a 3.73 posi, and disc brakes with an internal parking brake. I got mine from a NY salvage yard for 350.00 delivered but it was missing most of the brake parts when received.
Here are pics as delivered. Note that the only brackets welded to the axle tubes are leaf spring/snubber mounts and a steel strap to anchor the brake line. Also note that the sway bar mounts in front of the diff housing and over the pinion.
Here are pics as delivered. Note that the only brackets welded to the axle tubes are leaf spring/snubber mounts and a steel strap to anchor the brake line. Also note that the sway bar mounts in front of the diff housing and over the pinion.
#2
Re: ZR2 8.5 INSTALL
here is pics of axle positioned in car with stock wheels. It pushes the tire out some but stil plenty of clearance. Note the large gap between the top of tire and wheel well. The car is at stock ride height. Distance from top of wheel well to ground is 28 7/8 in.
#3
Re: ZR2 8.5 INSTALL
pics of axle under car. You can see that it lines up well with stock lca position. The new wheel in the pics is a 17x9 with 6"bs. Clears well wit stock lca and could go wider with tubular control arms. I'm looking to run the 17x9 on the street and will try to fit a 17x11 with 7.75 bs for the track.
#4
Re: ZR2 8.5 INSTALL
You are going to need to change the differential in that rear end. The only limited slip differential that is offered in those is the Governor Lock, which isn't going to work worth a crap for what you are doing. I would recommend the Truetrac for what you are wanting to do with it.
#6
Re: ZR2 8.5 INSTALL
You are going to need to change the differential in that rear end. The only limited slip differential that is offered in those is the Governor Lock, which isn't going to work worth a crap for what you are doing. I would recommend the Truetrac for what you are wanting to do with it.
#7
Re: ZR2 8.5 INSTALL
I have done extensive modifications to the floor and frame from under the front seats to above the centerline of the rear axle to accomodate the 3 link and lower the car 3 inches while still allowing 3 inches of compression travel. I won't get into any detail of those mods as I want to keep this to just the axle mods and install. Most of the axle mods can be used with a stock floorpan. The entire build of this car is in the fabrication forum under "Homebrew roadracer".
I have had this car for a few years and had spent a lot of time taking measurements under the car. I plotted them onto large sheets of graph paper and ran through multiple setups to get the best suspension geometry that I thought I could duplicate with the tools and talent I have. Most of the bracketry was designed using the dimensions from the graph models. After looking at numerous parts on the web and in catalogs I found several common, pre-made suspension brackets that I could modify to work and this saved a lot of time and money.
After I cut off the stock spring perches and brake line brackets I started with the LCA axle brackets. The brackets are from Allstar Performance, a primarily circle track parts company. I chose this bracket mainly because of its length and that it doubles as the coilover mount. Problem #1, almost all universal axle brackets are designed for 3" dia. axle tubes. An 8.5 or 8.6 10 bolt from a car or truck has 3" axle tubes but the ZR2 axle tubes are necked down to 2 5/8 dia so GM could use the same rear brakes as the standard S10 and Blazer. I solved this by getting some 3/16 wall tubing that was 2 3/4 dia., cutting it in half and then hammer form it to fit over the ZR2 axle tubes.
I have had this car for a few years and had spent a lot of time taking measurements under the car. I plotted them onto large sheets of graph paper and ran through multiple setups to get the best suspension geometry that I thought I could duplicate with the tools and talent I have. Most of the bracketry was designed using the dimensions from the graph models. After looking at numerous parts on the web and in catalogs I found several common, pre-made suspension brackets that I could modify to work and this saved a lot of time and money.
After I cut off the stock spring perches and brake line brackets I started with the LCA axle brackets. The brackets are from Allstar Performance, a primarily circle track parts company. I chose this bracket mainly because of its length and that it doubles as the coilover mount. Problem #1, almost all universal axle brackets are designed for 3" dia. axle tubes. An 8.5 or 8.6 10 bolt from a car or truck has 3" axle tubes but the ZR2 axle tubes are necked down to 2 5/8 dia so GM could use the same rear brakes as the standard S10 and Blazer. I solved this by getting some 3/16 wall tubing that was 2 3/4 dia., cutting it in half and then hammer form it to fit over the ZR2 axle tubes.
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#8
Re: ZR2 8.5 INSTALL
I made some axle stands that bolted to the lug bolts. These held the axle in place and allowed me complete access to the axle tubes and center section. They also allowed me to remove and install the whole assembly many times and always get it back in the same location.
Once I had the axle in place I used some long I-bolts to determine shock length and location. As I mentioned in an early post I have cut out a substantial part of the floor and sub frame but oddly enough the top shock mount is very close to the stock location. This would work with the stock floor pan in place with only minor mods and a stud mount on top of shock.
Also note that the lca brackets have been swapped side to side. I did this to get the shock closer to the tire to maximize their effect on handling. Moving the lca to the inside places the front of the lca inline with the boxed frame section under the rear seat. To make this work on a stock floor pan the brackets would need to be swapped so that the shock is on the inside.
Because this car is being built as a dedicated track day car I wanted to optimize the new suspension as much as possible and part of that was to try and minimize roll steer. To accomplish this I made the lca's as long as possible which turned out to be 23 1/2 inches center to center. Factory lca's are about 19 1/2.
Once I had the axle in place I used some long I-bolts to determine shock length and location. As I mentioned in an early post I have cut out a substantial part of the floor and sub frame but oddly enough the top shock mount is very close to the stock location. This would work with the stock floor pan in place with only minor mods and a stud mount on top of shock.
Also note that the lca brackets have been swapped side to side. I did this to get the shock closer to the tire to maximize their effect on handling. Moving the lca to the inside places the front of the lca inline with the boxed frame section under the rear seat. To make this work on a stock floor pan the brackets would need to be swapped so that the shock is on the inside.
Because this car is being built as a dedicated track day car I wanted to optimize the new suspension as much as possible and part of that was to try and minimize roll steer. To accomplish this I made the lca's as long as possible which turned out to be 23 1/2 inches center to center. Factory lca's are about 19 1/2.
#9
Re: ZR2 8.5 INSTALL
The top control arm mount was a bit more complicated as you can't weld directly to the cast center section. I have seen some posts from other TGO members who have tried to make torque arm mounts for other 10 and 12 bolt housings that were extremely large, complicated and heavy. I was hoping to come up with a design that was much simpler and compact. The tubing is 1 3/4, .120 wall dom mild steel. The plates at the sides are 1/4 plate and the actual bar mount is 1/8 mild steel. Some additional bracing will be added later.
In the last pic you can see that both the upper and lower control arms are parallel at the intended ride height. The front mounting brackets allow for changing the instant center and anti squat, and are angled so that the bars can be re-positioned without having to readjust their length.
In the last pic you can see that both the upper and lower control arms are parallel at the intended ride height. The front mounting brackets allow for changing the instant center and anti squat, and are angled so that the bars can be re-positioned without having to readjust their length.
#10
Re: ZR2 8.5 INSTALL
For the panhard bar I used a couple premade braces from Allstar that have 6 3/4" adjustment holes. With the axle housing at ride height I positioned the frame side bracket so the top hole was at the factory position and tack welded it to the axle housing with a piece of scrap steel to hold it in place. I then made some poster board patterns to make the actual frame mount from.
#11
Re: ZR2 8.5 INSTALL
to make sure I have no clearance issues with the 315-35r17 on 17x11 wheels I am doing a mini tub and also moving the panhard bar in a little. I actually shortened it by 3 1/2 inches, moving the mounting points inward 1 1/4 per side. To set the location of the axle side bracket I made a temporary panhard bar from wood scrap and then plumbed and squared the axle bracket.
Moving the brackets in had the added benefit of allowing me to run a brace from the left side lca bracket to the left side panhard bracket. This is made from 1 1/4 x.120 sq tubing. The top brace is 1/4 steel plate. To help minimize the lateral forces on both panhard braces and also make a little more room for the fuel cell I moved the mounting points about an inch closer to the diff housing. I can still get the stock stamped steel cover off with the panhard bar in place. I added one more brace from the left axle tube to the 1 1/4 sq tube.
Moving the brackets in had the added benefit of allowing me to run a brace from the left side lca bracket to the left side panhard bracket. This is made from 1 1/4 x.120 sq tubing. The top brace is 1/4 steel plate. To help minimize the lateral forces on both panhard braces and also make a little more room for the fuel cell I moved the mounting points about an inch closer to the diff housing. I can still get the stock stamped steel cover off with the panhard bar in place. I added one more brace from the left axle tube to the 1 1/4 sq tube.
#12
Re: ZR2 8.5 INSTALL
The last piece to address was the sway bar. I had originally hoped to use the stock camaro piece as it bolts to the axle tubes with the stock brackets in the stock camaro location. My problem was that the ends of the sway bar interfered with the coil overs. I don't think this would be a problem if they were mounted in the stock location.
After a little head scratching I realized the the ZR2 sway bar would work if I mounted it upside down. Originally it mounted in front of the diff and above the pinion. Now it mounts in front and below the pinion. The car gods smiled on me a s the distance between the ends of the sway bar matched the inside distance between my fabricated frame rails. I made up some rod-end endlinks and then boxed the ends of the sway bar with 1/8 steel and added 3 adjustment holes that will aid in fine tuning the roll stiffness.
After a little head scratching I realized the the ZR2 sway bar would work if I mounted it upside down. Originally it mounted in front of the diff and above the pinion. Now it mounts in front and below the pinion. The car gods smiled on me a s the distance between the ends of the sway bar matched the inside distance between my fabricated frame rails. I made up some rod-end endlinks and then boxed the ends of the sway bar with 1/8 steel and added 3 adjustment holes that will aid in fine tuning the roll stiffness.
#13
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Re: ZR2 8.5 INSTALL
With all that welding on the axle tubes, you may want to put the diff in a jig and recheck it's alignment. As thick as the tubes are, they'll still warp after being welded.
#14
Re: ZR2 8.5 INSTALL
Here are pics of the finished project aside from sandblasting and painting. The panhard bar and diagonal brace are aluminum hex w/ 3/4 rod ends as are all the suspension links except for sway bar end links are 1/2".
#17
Re: ZR2 8.5 INSTALL
The complete build up on the car is on the fabrication forum under home brew road racer. Lots of pics there. I have worked my way forward and have totally re engineered the frame structure in the center of the car and installed raised floor pans. The last 10 to 12 inches of the stock front frame rails were relocated away from the transmission to make room for long tube headers and true duals (the mufflers tuck up in the raised floor pans beneath the front seats.
NEW FRAME STRUCTURE
Tied in to relocated front frame
NEW FRAME STRUCTURE
Tied in to relocated front frame
#18
Senior Member
Re: ZR2 8.5 INSTALL
Can this swap be simplified for an unmodified car?
Need to ditch this 7.5, going for the cheapest route possible. Is it possible to take the brackets from my stock rear and weld them on to this axle in the correct locations and use stock geometry for shocks/springs etc?
I've found an 03 ZR2 rear with brakes etc for $150...
Need to ditch this 7.5, going for the cheapest route possible. Is it possible to take the brackets from my stock rear and weld them on to this axle in the correct locations and use stock geometry for shocks/springs etc?
I've found an 03 ZR2 rear with brakes etc for $150...
#20
Senior Member
Re: ZR2 8.5 INSTALL
I was planning an 8.8 swap from a ranger/mustang, but I have 26 spline axles so now I'm searching for a different option, so I was already planning on building a T/A mount.
Will my drive shaft length change?
Will my drive shaft length change?
#21
Re: ZR2 8.5 INSTALL
The ZR2 axle housing is about 3/4" wider per side. The stock Z28 wheels with 255,60r15 tires fit inside the wheel well with no mods needed to the fender lip. Also GM reduced the OD of the axle tubes just after they come out of the center housing and necked them down to the size of the 7.5/7.6 axle tubes. The ZR2 also has the same 4 bolt axle tube flange as the 4th gens with rear disc. With the axle tubes being the same diameter as the 7.5 swapping the brackets from the old axle to the ZR2 shouldn't be an issue. The only brackets that need to be removed from the ZR2 are the leaf spring mounts.
Because the center section is larger than the 7.5 and the pinion flange extends farther out from the housing, I had to shorten my stock steel drive shaft an 1 1/4". Also the ZR2 pinion flange uses the larger 1330 u-joint, not a 1310 like the 3rd gen so a conversion joint will be needed.
Hope this info helps. Let me know what you plan to do for the torque arm mount.
Dave
#22
Senior Member
Re: ZR2 8.5 INSTALL
Awesome, thanks for the reply. I plan to get those year one 17x9 snowflakes for the car, but I'm not too worried about those not fitting with this rear. Goals for the car is something I can autocross here and there, with a trip to the strip once or twice a year (however, I tend to beat on the car a bit every time I take it out). HP goals are eventually ~450 with cam, heads and headers, but this rear should handle this.
Here is my first design, using 1/4" plate, bolted over the cover with longer cover bolts. The "A-frame" from the 1/4" plate will be .125 square tubing (likely 1.5), I'll bolt it to the 1/4" plate so I can pull the plate off. Not sure if the lateral brace would be needed or not.
This is my second idea, sort of stolen from something I saw on LS1tech for an 8.8 swap, this one has more of a negative effect on ground clearance, and the rotational force is put on the tubes and not the diff.
I plan to use a founders T/A, the bolts for it are horizontal and it will also allow me to adjust for pinion angle.
I'm not a draftsman and these are unmeasured sketches, it's just the general idea I hope.
This swap seems to fit the ticket for me, and it will come out cheaper than the 8.8 swap would be. If I find the G80 isn't working, I'll put a TruTrac in it.
I'm currently apprenticing as an aircraft structural tech, so my Fab skills are decent, and I've done enough welding that I'm confident I can pull it off as long as I take my time (father is a certified pressure vessel welder so he can check it over for me)
I'm doing a scrap yard day again this weekend so hopefully I can find a third gen that I can grab an axle from to take apart, and I'll grab this rear that I found and some S-10 backing plates (I'm assuming they use the same brakes, the guy with the axle says they aren't on the axle).
Here is my first design, using 1/4" plate, bolted over the cover with longer cover bolts. The "A-frame" from the 1/4" plate will be .125 square tubing (likely 1.5), I'll bolt it to the 1/4" plate so I can pull the plate off. Not sure if the lateral brace would be needed or not.
This is my second idea, sort of stolen from something I saw on LS1tech for an 8.8 swap, this one has more of a negative effect on ground clearance, and the rotational force is put on the tubes and not the diff.
I plan to use a founders T/A, the bolts for it are horizontal and it will also allow me to adjust for pinion angle.
I'm not a draftsman and these are unmeasured sketches, it's just the general idea I hope.
This swap seems to fit the ticket for me, and it will come out cheaper than the 8.8 swap would be. If I find the G80 isn't working, I'll put a TruTrac in it.
I'm currently apprenticing as an aircraft structural tech, so my Fab skills are decent, and I've done enough welding that I'm confident I can pull it off as long as I take my time (father is a certified pressure vessel welder so he can check it over for me)
I'm doing a scrap yard day again this weekend so hopefully I can find a third gen that I can grab an axle from to take apart, and I'll grab this rear that I found and some S-10 backing plates (I'm assuming they use the same brakes, the guy with the axle says they aren't on the axle).
#23
Re: ZR2 8.5 INSTALL
You might as well go ahead and change the differential before you put the rear end in the car. The Governor Lock will not work the way you want it to, even if it is not broke. The Gov Lock is set up so that it only locks at low speed. Once you get above around 10 MPH it will no longer lock and you will be spinning one wheel.
By the way, the G80 code is not only used for the Gov Lock. It is used for all limited slip differentials in the GM cars and trucks. G80 in a truck gets you the Gov Lock. G80 in a 3rd gen or early 4th gen got you the Auburn, G80 in a 2nd gen got you the Traction Lock and G80 in a '60s or early '70s Chevy got you the Eaton Posi.
By the way, the G80 code is not only used for the Gov Lock. It is used for all limited slip differentials in the GM cars and trucks. G80 in a truck gets you the Gov Lock. G80 in a 3rd gen or early 4th gen got you the Auburn, G80 in a 2nd gen got you the Traction Lock and G80 in a '60s or early '70s Chevy got you the Eaton Posi.
#24
Senior Member
Re: ZR2 8.5 INSTALL
Thanks for the G80 education. I thought it was just Gov lock (I've only had one other GM vehicle with a locking rear).
Any input on my T/A plans? I feel like the one using the bolted on 1/4" plate would be sturdy enough.
I think what I'll do for the spring perches is tack them in to position and then have a shop do the rest of the welding. I'm confident I could do it, but I don't want to mess around with a failure.
Any input on my T/A plans? I feel like the one using the bolted on 1/4" plate would be sturdy enough.
I think what I'll do for the spring perches is tack them in to position and then have a shop do the rest of the welding. I'm confident I could do it, but I don't want to mess around with a failure.
#26
Senior Member
Re: ZR2 8.5 INSTALL
Well, it has started. grabbed a 4th gen housing for $50, I'll use it for the mounting locations... I think I remember seeing a ZR2 in another pick'n'pull so I'm gonna see next weekend, if so, I can grab that one for $50... If it's not there, I'll grab the $150 I found.
These things aren't overly heavy, but when you're carrying them for a few hundred yards through the junk yard, it's enough of a work out lol... But for $50 "if you can carry it" I'll make it work.
If I can get this $50 axle, I'll have the thing built for under $1000 US including a truetrac and a founders T/A... not bad.
Once I start the actual process, I'll start my own thread since it's going in to a stock suspension car for people to possibly follow as an example.
These things aren't overly heavy, but when you're carrying them for a few hundred yards through the junk yard, it's enough of a work out lol... But for $50 "if you can carry it" I'll make it work.
If I can get this $50 axle, I'll have the thing built for under $1000 US including a truetrac and a founders T/A... not bad.
Once I start the actual process, I'll start my own thread since it's going in to a stock suspension car for people to possibly follow as an example.
#27
Re: ZR2 8.5 INSTALL
Awesome, thanks for the reply. I plan to get those year one 17x9 snowflakes for the car, but I'm not too worried about those not fitting with this rear. Goals for the car is something I can autocross here and there, with a trip to the strip once or twice a year (however, I tend to beat on the car a bit every time I take it out). HP goals are eventually ~450 with cam, heads and headers, but this rear should handle this.
Here is my first design, using 1/4" plate, bolted over the cover with longer cover bolts. The "A-frame" from the 1/4" plate will be .125 square tubing (likely 1.5), I'll bolt it to the 1/4" plate so I can pull the plate off. Not sure if the lateral brace would be needed or not.
This is my second idea, sort of stolen from something I saw on LS1tech for an 8.8 swap, this one has more of a negative effect on ground clearance, and the rotational force is put on the tubes and not the diff.
I plan to use a founders T/A, the bolts for it are horizontal and it will also allow me to adjust for pinion angle.
I'm not a draftsman and these are unmeasured sketches, it's just the general idea I hope.
This swap seems to fit the ticket for me, and it will come out cheaper than the 8.8 swap would be. If I find the G80 isn't working, I'll put a TruTrac in it.
I'm currently apprenticing as an aircraft structural tech, so my Fab skills are decent, and I've done enough welding that I'm confident I can pull it off as long as I take my time (father is a certified pressure vessel welder so he can check it over for me)
I'm doing a scrap yard day again this weekend so hopefully I can find a third gen that I can grab an axle from to take apart, and I'll grab this rear that I found and some S-10 backing plates (I'm assuming they use the same brakes, the guy with the axle says they aren't on the axle).
Here is my first design, using 1/4" plate, bolted over the cover with longer cover bolts. The "A-frame" from the 1/4" plate will be .125 square tubing (likely 1.5), I'll bolt it to the 1/4" plate so I can pull the plate off. Not sure if the lateral brace would be needed or not.
This is my second idea, sort of stolen from something I saw on LS1tech for an 8.8 swap, this one has more of a negative effect on ground clearance, and the rotational force is put on the tubes and not the diff.
I plan to use a founders T/A, the bolts for it are horizontal and it will also allow me to adjust for pinion angle.
I'm not a draftsman and these are unmeasured sketches, it's just the general idea I hope.
This swap seems to fit the ticket for me, and it will come out cheaper than the 8.8 swap would be. If I find the G80 isn't working, I'll put a TruTrac in it.
I'm currently apprenticing as an aircraft structural tech, so my Fab skills are decent, and I've done enough welding that I'm confident I can pull it off as long as I take my time (father is a certified pressure vessel welder so he can check it over for me)
I'm doing a scrap yard day again this weekend so hopefully I can find a third gen that I can grab an axle from to take apart, and I'll grab this rear that I found and some S-10 backing plates (I'm assuming they use the same brakes, the guy with the axle says they aren't on the axle).
If you did just plan #1 I think you would have to goe with 1/2 steel plate on back of diff and make it go all the way around. The cover bolts are only 6mm so you would need to use them all for strength. Also if you use studs instead of bolts you could leave the TA mount plate on the diff if you had to remove the cover to service the gears inside.
If you did the combo you could get away with using the 1/4 plate, but again make it go all the way around the rear opening, mount it with studs and put the cover over the mounting plate.
Post some pics as you go. I think a lot of people would be interested how it turns out.
#28
Senior Member
Re: ZR2 8.5 INSTALL
Thanks.
I'm not sure how far I'll get cutting a 1/2" plate that is the entire circumference with a jig saw, so I'll make a cardboard template and bring it to a machine shop for them to cut out for me... Plus drilling all those holes through 1/2" isn't much fun without a proper drill press. If I can get away without doing the tubes over the axles that would be great.
I'm not sure how far I'll get cutting a 1/2" plate that is the entire circumference with a jig saw, so I'll make a cardboard template and bring it to a machine shop for them to cut out for me... Plus drilling all those holes through 1/2" isn't much fun without a proper drill press. If I can get away without doing the tubes over the axles that would be great.
#29
Re: ZR2 8.5 INSTALL
WTR, you probably would not need the tubes over and under the axle but it wouldn't hurt to tie the plate in to the left axle tube. I am thinking a flat 1/4" plate similar to a 4 link bracket, without all the holes, welded to the back side of the axle tube and to your 1/2" cover plate. It could be shorter on top than the bottom as the top of your torque arm should mount at or below the pinion center line.
#30
Senior Member
Re: ZR2 8.5 INSTALL
WTR, you probably would not need the tubes over and under the axle but it wouldn't hurt to tie the plate in to the left axle tube. I am thinking a flat 1/4" plate similar to a 4 link bracket, without all the holes, welded to the back side of the axle tube and to your 1/2" cover plate. It could be shorter on top than the bottom as the top of your torque arm should mount at or below the pinion center line.
Is the distance from the outer axle flange to the outer flange where the disc backing plate bolts to different than from that of an LS1 rear?
I have every piece needed to use the LS1 rear brakes, but the ZR2 rotor looks deeper than the LS1 rotor, so I'm assuming that mount on the tube is in a bit further on the ZR2... I can easily get spacers machined if that is the case. I want to use the LS1 rear set up because it's slightly larger and should perform a bit better and I have drilled rotors that match what I have for the front.
I know I could figure that one out on my own, but I don't pick up my ZR2 rear until this coming weekend and won't be able to play with it until next week and my mind doesn't shut off about this stuff.
#32
Senior Member
Re: ZR2 8.5 INSTALL
Of course, after I pose a question I find the info, the 4wd rear rotors on an S-10/Blazer are deeper then the 2wd, The calipers and caliper mounts appear to be the same between the two, so it means either the 4wd backing plates are different from the 2wd (which rock auto seems to confirm), or the mounting surface on the tube is closer to the pumpkin on the 4wd trucks... Which I think I've read is the case and is a 3/4" difference... Luckily I can take the ends off my Fbody housing and use as spacers with a little bit of work since the bolt patterns for the backing plates are all the same.
I remember looking at a blazer rear disc set up yesterday at the yard and thinking to myself that the rotor was very different from the LS1 rear set up that I had in my hand.
And why I'm so stuck on using the LS1 rear disc set up over the ZR2 set up, I'm not sure, as I doubt it will make any noticeable difference to me between the two, other than there are more performance options for the LS1 stuff obviously.
I remember looking at a blazer rear disc set up yesterday at the yard and thinking to myself that the rotor was very different from the LS1 rear set up that I had in my hand.
And why I'm so stuck on using the LS1 rear disc set up over the ZR2 set up, I'm not sure, as I doubt it will make any noticeable difference to me between the two, other than there are more performance options for the LS1 stuff obviously.
#33
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Car: '86 Camaro, '94 Camaro, 3 others
Engine: LG4 ->L29, L32->LR4, L36, LG4, L31
Transmission: 700R-4, T5WC, 4L80E, SM465, 4L60E
Axle/Gears: 3.42, 3.23, WTB/WTT 2.93
Re: ZR2 8.5 INSTALL
If I wanted an 8.5", I'd rather start with the one from a '79-'81 T/A WS6. It's already the correct width, the correct lug pattern, good disc brakes, the strength is there without the excess weight of the truck center requiring the tubes to grow to 3", which looks dumb and adds more useless weight. The 2nd gen 8.5" can also be made 30-spline. ZR2s are rare, 2nd-gens are more often found in the salvage yards. Plus Novas, Omegas, Venturas, and Apollos used the same housing.
#34
Re: ZR2 8.5 INSTALL
Actually the X body (Nova, Omega, Ventura and Apolo) rear end is 1 inch narrower than the 2nd gen Camaro rear end. The X body rear end is 60 inches and the 2nd gen is 61 inches.
#35
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Join Date: Apr 2013
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Car: '86 Camaro, '94 Camaro, 3 others
Engine: LG4 ->L29, L32->LR4, L36, LG4, L31
Transmission: 700R-4, T5WC, 4L80E, SM465, 4L60E
Axle/Gears: 3.42, 3.23, WTB/WTT 2.93
Re: ZR2 8.5 INSTALL
shafts, or housing, or both? ( all 3, technically )
Also, the '99-'04 Mustang GT 8.8" assembly is really close in width to the stock 3rd-gen assemblies.
Also, the '99-'04 Mustang GT 8.8" assembly is really close in width to the stock 3rd-gen assemblies.
#36
Re: ZR2 8.5 INSTALL
All of it. The axles are each 1/2 inch shorter and the housing is 1 inch narrower.
The FOX and SN95 Mustang 8.8 has almost the same size axle tubes as the 3rd and 4th gen Camaro.
The FOX and SN95 Mustang 8.8 has almost the same size axle tubes as the 3rd and 4th gen Camaro.
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