C notched and dropped???

[broey]

If a c notch is boxed in like it should be (which most are) then its probably the strongest part of the frame. Just because the factory built something a certain way, it doesn't make it the best way. Thats why companies are able to sell performance parts. To improve on factory flaws. My truck lays pinch weld and is just as strong, If not stronger than when it was stock.

[kieth]

Originally Posted by 66-PMD-GMC

Look, I am not bagging on anyone here, just trying to understand.
It seems the largest percentage of people starting threads on this forum are C notching and or dropping their trucks.
I can't personally see the allure but to each his own.
My question is; does everyone here realize the compromise in structural integrity they are making by hacking up the frame like this??
In a rear or side impact these frames will buckle and fold big time.
I recently saw a Z notched truck that was reinforced and built in such a manner that it seemed the more logical way to "slam" a guys truck.
My other question is; is everyone doing this (slamming their trucks) because it improves the looks of the truck and the handling or is it just a fad that the hobby is going through??

To answer the first post I think people c notch their trucks to get it to set lower, I may be notching my truck later for another reason: to get it to set lower but still have a full range of travel. If it takes a c notch , truss, circle truss , etc what I do will depend on what is required to make it safe and have a good ride. Others do it to slam the truck on the ground, like all hobbies there are differing attitudes and styles. I feel your question was presented in a very nice way and do not feel everyone should have ganged up on you. I learned a long time ago to not respond to persons who flame me on a forum, everybody loses so I just ignore it and go on. Hope your truck is coming along and you are getting as much out of this forum as I am.
One surprising thing about this forum, it is very active, and this is because it supports all variations in the form of building older chevrolet pickups. If yo go to other forums you will see that they might be old school or might be more hip and they tend to exclude others who do not share their opinion of what we should be doing to our trucks. You will also notice that they are not as active......there is more going on here than on any 5 other forums......I enjoy it and the divergent views. Kieth

[roofingbloke]

Hi All. I have done a lot of reasearch on both c notch and both step notch,

I live in the UK and i am going with a step notch and wil also be towing a small caravan (90lbs ball wieght)

I have looked at loads of threads about the scientific points of strength etc etc,

I feel that if the chassis is boxed then the strength id stepped up drematicly,

Am i wrong in thinking thst recent posts indicate that bolt in applications are stronger thsn weld in applications.

[lakeroadster]

Originally Posted by roofingbloke

Am i wrong in thinking thst recent posts indicate that bolt in applications are stronger thsn weld in applications.

I have yet to see a commercially available bolt in notch that increases original frame strength.

There are numerous commercially available weld in notches/trusses that are as strong or stronger than the original frame.

Read this thread:Frame Notch Based On Strength

[N2TRUX]

Ok, so now we are actually having a discussion on the original topic. Thats exactly what I was referring to in my first response regarding researching the topic. Now on to the meat of things.

Why do a C-notch rather than a frame Z? As Scoti mentioned, its a matter of simplicity. You can buy a bolt or weld in notch, and have it installed in a day. Even if you opt to build a small notch it's easy enough to do. The end result is a truck that is lowered as far as your going to get with out sacrificing functionality of the bed.

Did that end result compromise the integrity of the frame at the C notch? In many cases, yes it now has a stress point that is possibly weaker than before it was cut.

Even if you use Johns examples and have gone the extra steps to reinforce the notch to a point that is is structurally as strong, or stronger than before the cut, it is likely that you have created a new "crumple zone". My thoughts are that in the event of a rear impact the frame would fold at that point.

Would it be better to Z the back of the frame and raise the bed floor? That depends on a lot of factors. Starting with materials used, design integrity, and installers skills. If you use tubing that meets or exceeds the OEM frame strength, and a design that utilizes proper structural geometry, you have the potential to have a very strong back half. Of course all that goes out the window if the components are not installed by a competent welder.

In the end, its just a matter of what works best for your build. The average enthusiast is going to buy a prefabbed notch, or build their own from a piece of pipe and some boxing plate and call it good. It might not be the perfect solution, but it has proven to be adequate in most applications.

[BarnFind]

Ive always preferred the c - notch. It is easy and I didnt want to cut up the bed. Ive done the 5/7 drop w/c-notch on my new Chevy trucks since the late 80"s. I towed my boat with them since day one with no problems. As a matter of fact, my brother is still driving my 94 with a c-notch. Granted, Ive never been rear ended so I have no idea how it would score in a crash test but, what street rod out there would.
This may have been a good question 25 plus years ago. "I" have never heard of a failure from a properly installed one. Sean

[66-PMD-GMC]

OK, so now that the points have been touched on....
Why not take the rear section of an A body GM... (68-72) GTO, Lemans, Malibu, Skylark etc.. wagon and section that in, boxing the frame while your at it?
You would get the increased travel, 4 link (factory trailing arms) and the frame strength in the end.
Here is a link..
http://image.highperformancepontiac...._GTO+Frame.jpg
Has anyone tried this?

[SCOTI]

Originally Posted by 66-PMD-GMC

OK, so now that the points have been touched on....
Why not take the rear section of an A body GM... (68-72) GTO, Lemans, Malibu, Skylark etc.. wagon and section that in, boxing the frame while your at it?
You would get the increased travel, 4 link (factory trailing arms) and the frame strength in the end. Has anyone tried this?

I'm sure someone has tried it just like swapping the GM A/F body front clips into older trucks. I'm not too sure the geometry is better vs. the truck arm set-up or if that design would allow for more rear suspension travel.

IMO, if you're capable of doing that kind of fab work, why use the GM based C4L rear geometry which is compromised @ best? Anyone that has those fab skills would more than likely just build a 'universal' 4-bar (either parallel or triangulated) along w/a rear frame section. Doing so requires a lot more than what a c-notch entails & would take up more time, space, & budget than most care to do.

[lakeroadster]

Originally Posted by 66-PMD-GMC

OK, so now that the points have been touched on....
Why not take the rear section of an A body GM... (68-72) GTO, Lemans, Malibu, Skylark etc.. wagon and section that in, boxing the frame while your at it?
You would get the increased travel, 4 link (factory trailing arms) and the frame strength in the end.
Here is a link..
http://image.highperformancepontiac...._GTO+Frame.jpg
Has anyone tried this?

I guess "why" would be my question? The stock "Truck arm" suspensions used in our trucks is a great design and it is bullet proof. Did you know that NASCAR used this same suspension design as the basis for it's Cup cars? And there are even kits being sold that replicate the so called Nascar "Truck Arm" for installation in cars: Truck Arm in a Camaro. We have the original, why setlle for less than the best?

In a weekend, with only minimal tools and minimal $$$, a fella can pull the bed off his truck, weld in a notch, rework the upper shock mounts, install new rear lowering springs and be back on the road before Monday morning.

Bottom line, that is what is appealing about notching the existing frame. It's quick and relatively painless from the perspective of $$$.

[ihssalky]

I personally went with the c notch. I know that i gave up rear impact strength. Its easy to see because the frame is no longer strait. Really is this a bad thing? Vehicles made today are made in such a way to absorb impact and sustain damage to keep the passengers safe. A c notch can work the same way. It is far enough behind the passengers to still be safe when crushed. I looked at more bracing to stiffen the notch, and i have helped its strength. I believe that a z frame might be a hazzard. When using a z you have to alter the frame in the front and rear. This makes for two weak points. With a drop front suspension vs a z you keep the frame intact. Basically for the same reason a rear frame alteration is bad, so is a front one. The front one is closer to the passengers so it could be potentially worse in a crash if it were to fail at the weld /z joint.
I think that one problem you see alot is rear tank conversions. It is in that impact zone. I have elected to move mine in fromt of the notch in the front of the bed. This seems to be forward of any crush area in a strait frame area and still out of the cab.
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[INSIDIOUS '86]

"Just to get you started on the right path, a lowered truck that is not equipped with a hydraulic suspension hasn't been called a "Lowrider" in a few decades, so please adjust your terminology accordingly."

Scotti!
Posted via Mobile Device

[SCOTI]

Originally Posted by INSIDIOUS '86

"Just to get you started on the right path, a lowered truck that is not equipped with a hydraulic suspension hasn't been called a "Lowrider" in a few decades, so please adjust your terminology accordingly."

Scotti!
Posted via Mobile Device

??
Did I miss something?
Posted via Mobile Device

[CC69Rat]

My CNotch has 17 grade 8 bolts in it. It is plated on all 4 sides, and bolted on 3. IMO, it's stronger now than before it was cut. Just sayin .. With the right parts, I think it actually gives it strength. I havent regretted mine for a minute.. it's your truck, I say it's your decision.

[66-PMD-GMC]

Originally Posted by CC69Rat

My CNotch has 17 grade 8 bolts in it. It is plated on all 4 sides, and bolted on 3. IMO, it's stronger now than before it was cut. Just sayin .. With the right parts, I think it actually gives it strength. I havent regretted mine for a minute.. it's your truck, I say it's your decision.

I have done tons of reading and digging through the internet since starting this thread and I have found several things that I did not know.
As a car and truck builder/fabricator I am always interested in what is going on in the hobby.
1- To get the kind of ride height that many builders are going for, a simple "C-notch" doesn't come close to giving the builder enough clearance for them to "lay frame".

2- The tire wheel combinations used by some builders not only require the rear frame to be altered, they also require a pretty expensive "drop member" and front suspension to "lay out" the front end.

3-The inner wheel wells become useless and need to be highly modified to be used at all. I have seen trucks that the tires are an inch away from the hood.

4-After rereading my #1 post in this thread, I can see that I come off pretty arrogant and abrasive..
Sorry about that
Not my intension at all, I was simply trying to find out how the frame alterations being done, are being done and making the statement that a few that I have seen look pretty unsafe.... That is not to say all are, just some that I have seen.

I am still not into the big wheel look on the 60-66 trucks and the cool thing is I don't need to be..
I do respect what others do to their trucks and hope they respect what I do with mine.
Just setting the record straight.
Also, for anyone who might care. I have been working on a hidden roll cage for my pro-street truck, that incorporates an altered rear frame with a cage in the bed under a fiberglass bed cover and a roll cage in the cab that does not have the support links that go from the main hoop back to the frame.
What I have been designing could be used to reinforce the rear frame AND supply a platform for a raised bed floor.
I definately don't want that 4X4 roll bar look so that is why I have gone to such great trouble to develope something and also a reason I was/am interested in how builders are nothching frames..

[ChefCy]

i want to see the cage in the bed