b-body rear into a g-body?

[megaladon6]

i know it's wider but that works for me, and i'd change the axles anyway so it'd get the right bolt pattern. i'm just wondering if it'll bolt in. i just saw a thread on another forum (google search) where a guy says the spring perches lined up but he "drilled out the UCA bolt holes" and it worked. anyone ever see this before? g-body 8.5's are expensive as hell and are very hard to put disc brakes onto. but i want something that works correctly, not just well enough.
thanks

[megaladon6]

anyone think it's a stupid idea to try it?

[Josh]

How much wider are they? If it all lines up and you just order the proper back spaced wheels then I don't see a problem.
So you have no rear end now?
I have a non posi full rear end out of a 72 ElCamino, but you are a bit far away. I also have a pair of B-body axles already drilled for 5 X 4.75"
Josh

[megaladon6]

i think it's an inch wider on each side (90's caprice or roadmaster) but i plan on using c5 rims with spacers so it allows me to run a smaller spacer. so that's good. the standard bolt pattern on the tube flange also makes it easier to swap to disc brakes, which i need.
my problem is his statement that he drilled out the UCA bolt holes. i don't know exactly what he means. if it's a slight oblonging of the bolt hole in the UCA itself due to a difference in angle, will that cause binding or other issues? i'm concerned with handling, not drag strip performance.
right now i have the stock rear, i want to find out if it's a workable swap before i change things around. i'm hoping to find a cheap housing locally to test fit if nothing else. but i know i'm gonna blow the 7 5/8 in there now!
i'll let you know on the axles but i doubt it'll be any time soon
thanks

[Josh]

I guess I would check into that further before you invest any time or $. I just narrowed the 10 bolt in my Caprice for low backspace rims and each side was shortened about 1 and 3/4 inch. I had to temporarily remove the bump stop brackets and I was very close to the LCA brackets. I would find it hard to believe the g-body LCA brackets would be in the same position, but I guess it is possible.

[CRCRFT78]

I think this was covered before and the B-body rear won't bolt right up. I can't remember if it was discussed here or another forum but you should check MalibuRacing.com. Those guys should be able to give you a definite answer. I also have two 96 Impala posi rearends I would love to slap under a G-body in order to save with the disc brake issue. Keep us posted when you get a definite answer.

[oldskoolcaprice]

If you do go that route, do more research on it. Though, their both 8.5 rearends, the 94-96 b-body 9C1 cop car had a shorter axel than it's 94-96 impala ss brethern. The 9C1 axel came with 3.08 or 3.42 gears during those years. However, even a well taking care used 9C1 will have at least 100K miles on it. Believe it or not, there actually still considered fresh rearends, if they weren't ragged out.

[megaladon6]

I also have two 96 Impala posi rearends I would love to slap under a G-body

why couldn't you live in connecticut?! lol
actually the post that said he fit the b-body axle in was from maliburacing.com.... http://www.maliburacing.com/forum/vi...hp?f=2&t=66577
i don't plan on narrowing the rear, due to the deep B/S (7in?) on the c5 rims. i just found some possibly correct width numbers of 61in for the b-body and 58in for the g-body. i was looking at having to use 3in spacers with the stock size rear, the b-body would cut that in half.

[oldskoolcaprice]

Keep us posted with lots of pics. I'm intrested to know how it works out.

[CRCRFT78]

I'm a little skeptical after reading the thread from Malibu Racing. These rearends are available by the dozens at salvage yards but there are a few things that I would be concerned with.

[jackfrost]

buy one and try it out. let us know how it works.

[megaladon6]

well i decided that since it can be done, even if it may not work well in the end, i'd try it. just won one on ebay 130mi away for $230 complete with disc brakes. unfortunately it is the 9c1 rear so it's shorter (oh well, back to wheel spacers) but it only has 60k on it.
first i'm just going to measure everuthing and double check that it's close, since it's a driving car and the lug spacing is different.
as for the axles, for now can i just get them redrilled for the right lug spacing or do i need new axles?
other than the gears themselves and an install kit, is there anything i need (or need to know) to change from the 3.08 to a 3.73 gear? it has a posi in it now, i'm assuming it's an eaton or an auburn and not a gov-loc.
if i beat on it but don't drag race it, how long can i get away with c-clips? i really don't have the money for the floater conversion.
thanks for your help and advice.

edit: how do you measure the width? he measured the axle at 63in flange to flange, my "research" says 61in. and oldskoolcaprice said the 9c1 is shorter than the standard b-body 8.5. i find 58in for the g-body but not what points are used.

[Josh]

The axle difference is not because it is a 9C1, but that it is a disc brake set up. I would have to guess the housing is the same but there is more axle stick out for the discs.

[megaladon6]

i'm too tired to put the pics up but heres what i've got. (it's not much yet) the rear geometry is the same, 45* for the UCA's and 75* (from the axle) for the LCA's.
the g-body LCA's are 44.75in apart, the b-body's are 46in so it's only .625in difference per side. even poly bushings should be good but i'd highly recommend a heim or johnny joint for proper movement. although i guess the stock rubber on the axle side would be fine, it's just not the best for handling.
the G LCA's sit 1.5in to the rear of the axle center, i forgot to check the b-body but i think they sit a little farther to the rear, not by much(maybe 1/2in?).
i have to get some more measurements for the UCA axle mounts too. the G's sit 7.75in apart and the B's are 12in, but the G's are centered on the axle tube while the B's sit forward. i just have to do the trig and figure out the center point and other stuff.
for the shock mount you could relocate the hose hold down bolt (with disc brakes) and widen the hole for the shock bolt, or relocate the hose and use the oval hole below it. obviously if you use the oval hole it should be filled in. the original shock mount sits on the front of the axle, so i would just cut that off.
i forgot to look but IIRC the G's brake hose from the frame is on the D/S axle. that would need to be moved to the center of the axle, or a new braket made on the B's axle tube.
wheel mountind points are 61.5in apart with the rotors on. the outer rotor surface is 58.5in apart.
i doubt my measurements are EXACT, but they should be within 1/4in total.

[megaladon6]

and the axle is supposedly from a park rangers car, so i'm guessing it wasn't beat on TOO badly.

[megaladon6]

the spring perches are in the same spot, the UCA's are on the same line/center point.
from what i'm getting, you will need to shorten the UCA by 3in.
the LCA axle mounting points are in the same spot.
so from what i'm seeing you have to shorten the UCA, get good bushings or cut/weld the LCA's for a .6in spread, get a longer body-axle brake hose, and modify the holes for the shocks.
is there anything i missed/screwed up?

[novaderrik]

The axle difference is not because it is a 9C1, but that it is a disc brake set up. I would have to guess the housing is the same but there is more axle stick out for the discs.

i took the disc brakes off my 94 9C1 and put the drums from a 92 9C1 on it because all the guide pins had welded themselves permanently into the caliper brackets and i was too poor to buy new parts. it was a straight bolt in deal- i even took the drum brake lines off the 92 rear and it hooked right up and worked beautifully with the stock disc/disc master cylinder.
going by that, the axle offset on the 9C1 is the same as every other GM rwd car built since the mid 60's.
according to www.rockauto.com, all Caprices and Impalas from 94-96 use the same rear rotor.
according to the Dorman website, the wagon axleshaft is 3/8" longer than the regular Caprice/Impala SS axle- which would make the overall axle width 3/4" longer.

[megaladon6]

well, i finally got around to test fitting the rear. as expected there are some issues, but nothing i feel is insurmountable.
here are some more pics of how it sits.

the LCA's need to have the axle ends turned inboard about 8-10* but it might be possible to just turn the mounts without losing integrity and i think spherical ends will handle this misalignment.

the spring mounts are shorter than the g-body, not sure if this will be an issue. the other side is misaligned but i may just have the spring upside down or turned wrong. i also have the thicker g-body insulators in there, i'll have to try the B-s and see if it helps.

where i have the shocks mounted is obviously the wrong angle and is presently about 2in above it's normal spot., but i'm sure there's a good way around this. maybe just a steel plate welded in below it.

the UCA's need to be shortened by approx 3.25-3.5in (about 8.5in center to center total length)and again there's a slight angular difference, i haven't gotten a good number yet, but it also seems to be about 8*. rod ends won't help here unfortunately. i think i can bend the UCA axle side tabs to account for this. correction, i just did bend it to the correct angle. btw i'm using lakewood and BMR tubular for this, stock arms have enough flex to probably go in with no apparent angular issues

[big gear head]

The upper controll arm eyes are farther apart on the B body rear ends. I've considered building some 8.5 rear ends to fit the G body cars, but can't find anything that will work with the upper controll arm locations. The closest thing is the '64 to '72 A body rear ends, and they are at the wrong angle. I have a vew of each of these rear ends and I have measured them a few times to figure out how to make it work. I have decided that there isn't any easy way to do it.

[rixtrix1]

Somebody used to sell conversion upper control arms to mount an A body 12 bolt into a G body. It was a while ago, so it may have been Lakewood. I checked the old axle housing from my '66 Malibu against the B body 8.5 I just got, and it looks like there's a lot of difference, but using rod ends mounted offset to the arm centerline may work.Just a thought.
Ric