Author Topic: C-notch needed? lowering rear 4-5".  (Read 37541 times)

Offline chevymanrob

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C-notch needed? lowering rear 4-5".
« on: December 18, 2011, 01:36:14 pm »
ok all,
i am in the middle of my rear suspension cleaning and height adjustment. i am (just for fun)trying to do this using modified stock or really cheap methods. i have trimmed and adjusted the front leaf spring hangers and moved them up 4.25" and bolted them to the frame. i have 2 sets of springs available to me. i have a stock 5 spring pack and another 5 count with the longest leaf removed.
i have a few questions now...
1. how much (approximately of course) will the single leaf removed drop the rear?
2. will i need a c-notch with the 4.25" or possibly 5"with the 4 pack springs?
3. any rough ideas of what degree shim i should be looking at for pinion angle shims as i have to order them?
any other ideas/concerns/input would be welcomed too. i will add pics a little later.
also the truck in question is an 84 c10 swb and i am looking for that "sport truck" look. looking to do a single coil cut on the front or a 2.5" spindle. still up in the air with that as of yet.
rob
ex G-body drag fan. best was 11.86 on a 93 octane SBC street car.

Offline Isaac3384

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C-notch needed? lowering rear 4-5".
« Reply #1 on: December 18, 2011, 01:56:03 pm »
I can't tell you anything about the rear springs, but I would do a small notch in the rear, just for the additional clearance.

Instead of all the work you put in to relocating the hangers, why didn't you just make a flip kit to put the rear axle on top of the springs? Axle perches are cheap at tractor supply...

 

Offline chevymanrob

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Re: C-notch needed? lowering rear 4-5".
« Reply #2 on: December 18, 2011, 03:29:48 pm »
i didnt do the flip as i have no real welding skills and very little access to a welder...
ex G-body drag fan. best was 11.86 on a 93 octane SBC street car.

Offline 80stepsideguy

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Re: C-notch needed? lowering rear 4-5".
« Reply #3 on: December 18, 2011, 04:06:33 pm »
You dont need welding skills to do a flip on the rearend. I say buy this kit and you`ll need to get smaller bump stops.

http://www.ebay.com/itm/73-87-CHEVY-GMC-TRUCK-REAR-AXLE-FLIP-KIT-5-DROP-/150691420359?pt=Motors_Car_Truck_Parts_Accessories&vxp=mtr&hash=item2315e898c7

Its better to do this then mess with playing with pulling leafs out.I did this flip in my 80 but i ended up also doing a C notch kit.I heard people doing just the flip kit w/o a C notch kit but i wanted added insurance.

thanks
pat
1980 Chevy c10 restomod:  350/700r4 12 bolt 3.73 rearend iris blue metallic
1998 Chevy 1500 S/B 2wd
1970 cougar convertible: triple white 1 of 1
1931 Ford Model A roadster(family inherited)
2014 Hyundai Tucson Limited(my daily driver)
2023 Kia Sportage X Pro (her daily driver).

Offline 69byrd

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Re: C-notch needed? lowering rear 4-5".
« Reply #4 on: December 18, 2011, 04:21:06 pm »
I have a flip kit on my truck with no c-notch and I have no problems.  I also removed the bump stop mount and installed the bump stop to the frame.
84 C-10 Stepside       
54 Chevy Truck
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Offline chevymanrob

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Re: C-notch needed? lowering rear 4-5".
« Reply #5 on: December 18, 2011, 07:09:29 pm »
stepside i have never seen a flip like that. i was under the impression that you had to weld new perches to the axle tube. either way i have trimmed and remounted the front hangers and installed them so i am 99% sure i will be staying with that setup. i hope to have the final stuff done tuesday and will grab a few pics.
ex G-body drag fan. best was 11.86 on a 93 octane SBC street car.

Offline chevymanrob

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Re: C-notch needed? lowering rear 4-5". (pics added)
« Reply #6 on: December 20, 2011, 04:42:15 pm »
ok here are a few pics to show everyone my wreck...and the weird looking stuff on the top of the frame is masking tape where i had measurements and notes...just easier to keep it there!


ex G-body drag fan. best was 11.86 on a 93 octane SBC street car.

Offline HAULIN IT

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Re: C-notch needed? lowering rear 4-5".
« Reply #7 on: December 21, 2011, 09:03:31 pm »
Rob, I see a couple things that you should be aware of. (1) Moving the front perch on the frame 4" or so will only lower your truck a bit over half of that distance. (2) The pinion angle on your rear axle is going to be WAY positive. (3) The front spring eye should always be lower than the rear to control anti-dive, I suspect yours the way it is now is higher.
At this point you could install 2" drop rear shackles which are inexpensive & will go toward  lowering the truck & fixing the pinion angle.
Originally I had done my rear suspension similar. I put 2" drop rear shackles on & moved the front hangers like you did, however I stopped at something around 3".  The total drop at the center of the wheelwell was about 3 1/2". Not near enough for me so I ended up doing a flip. Hope this helps you in some way. Lorne
 

Offline chevymanrob

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Re: C-notch needed? lowering rear 4-5".
« Reply #8 on: December 23, 2011, 08:25:44 pm »
Lorne,
thanks for the advice. i didn't think about it until you mentioned it but moving only one suspension point would only affect the drop by 1/2 approximately like you said. i have some lowering shackles i am about to order. anysuggestions for a low cost angle finder? i dont want to drop alot of coin on one to use once. and what is the desired pinion angle for street use? the truck will be no more than 300 horsepower for a long time so ultimate traction isnt a big factor. i would like to avoid binding or vibrations though.
and again, thanks for the heads up. i didnt think of the angle/failed total drop.

rob
ex G-body drag fan. best was 11.86 on a 93 octane SBC street car.

Offline chevymanrob

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Re: C-notch needed? lowering rear 4-5".
« Reply #9 on: December 30, 2011, 06:59:05 pm »
shackles came today. pics to come soon.
ex G-body drag fan. best was 11.86 on a 93 octane SBC street car.

Offline chevymanrob

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Re: C-notch needed? lowering rear 4-5".
« Reply #10 on: January 08, 2012, 04:49:21 pm »
ok. i finally got the rear back in the truck today. it may be that i have had it on the jackstands way too long but it sure looks alot lower now!!! i measured the rearmost crossmember to the ground (the one with the big circles in it) and got about 20" from the ground to the bottom of the lip. could anyone please measure thiers and give me some comparison measurements? stock or not and please add info like drop amount and tire diameter. everyone feel free to add comments or advice.

ex G-body drag fan. best was 11.86 on a 93 octane SBC street car.

Offline HAULIN IT

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Re: C-notch needed? lowering rear 4-5".
« Reply #11 on: January 08, 2012, 06:12:25 pm »
Rob, I just went & measured for you...right @16". Tires are about 27". One thing to keep in mind, once the bed is installed you'll be another inch lower. Lorne

Offline chevymanrob

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Re: C-notch needed? lowering rear 4-5".
« Reply #12 on: January 09, 2012, 04:27:55 am »
i had my girl sit on that crossmember and it was 19.5" so i guessed the bed at about how much she weighs!!!! do you have any unloaded side views of your truck so i can gauge my ride height? i am trying to see how far down it will look now and then what i need to do up front as that is next on my list of things to do. i really do appreciate all the help.
ex G-body drag fan. best was 11.86 on a 93 octane SBC street car.

Offline HAULIN IT

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Re: C-notch needed? lowering rear 4-5".
« Reply #13 on: January 09, 2012, 10:11:14 pm »
i had my girl sit on that crossmember and it was 19.5" so i guessed the bed at about how much she weighs!!!! do you have any unloaded side views of your truck so i can gauge my ride height? i am trying to see how far down it will look now and then what i need to do up front as that is next on my list of things to do. i really do appreciate all the help.

Not gaining any points with the woman with posts like that! In her defence, I think it will come down a bit more than 1/2" once the bed is in place.
Here is a couple pictures, but one thing you need to keep in mind...I did a 2" angled (front to rear) bodydrop, so with my 16" to the crossmember lip I'm really 2" lower than that when looking at the bumper, wheelwell height, ect.

 

Offline chevymanrob

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Re: C-notch needed? lowering rear 4-5".
« Reply #14 on: January 15, 2012, 08:42:15 am »
thanks for the pics. there is a local guy with a truck that sits about how i want mine so i may go talk to him and see what he has done.
ex G-body drag fan. best was 11.86 on a 93 octane SBC street car.