Yes...If economics was the reason for all of our choices then we would all be on the Prius forum accessing it at our local Liberal Arts Communty College library computers.
Whether buying cubic inches in horse power, or crash zones; it's all at our own individual discretion and ability on what we spend money on. There's plenty of people from Berkley that can tell you why nobody should be allowed to drive a V8, or a car without seat belts & airbags....they are also willing to pass laws so we can't.
Heck, none of us can predict if it could be AXracers Miata or a suburban driving soccer mom, but when doing this build I can certainly spend so time to include a few basic safety features that if something happens, might make a diffence in the outcome.
The given:
I am buying a new chassis
The unknown:
How much more will it cost to buy a frame that is a perimeter shaped frame instead of a typical H frame

 

I said I was not going to post again in this topic, but I consider this a PUBLIC SERVICE ANNOUNCEMENT rather than a discussion about the difference between a chassis and a frame.
Many more fatalities and serious injuries, among young drivers especially, are the result of single car accidents caused by operator error.
Just two days ago here: "1 dead 1 seriously injured when the driver lost control and spun off the expressway", speed was likely a factor...
Frequently:
"vehicle dropped right wheels off pavement, driver over corrected and hit tree (or rolled over) off the left side of the road"...
"following too close"...
"driver was distracted by"...
"driving too fast for conditions"...
Etc etc etc.
You want to protect your young new drivers, enroll them in a good defensive driving school. For adults that THINK they are good drivers, take a local or professional autocross school for novices, that will open your eyes! For defensive driving courses in your area contact the local DMV or state police. For autocross schools search The Sports Car Club of America - Home and/or www.evoschool.com (disclaimer: the owner of the Evolution Performance Driving Schools is a good friend of mine, but I receive nothing for endorsing them. They even teach driving courses to US military Special Forces.)

Crash testing has proven surrounding them with rigid structures can do more harm than good when the force of an accident is not absorbed by the structure but rather is transmitted to the occupants. Trains and busses are big strongly built vehicles but the occupants are not particularly well off for it in a crash. Dale Earnhardt Sr. was killed in the last lap of the 2001 Daytona 500 when the force of hitting the wall @ 200 MPH was not absorbed by the rigid structure of his race car but transmitted to him breaking his neck and severing his spinal cord at the base of his brain.
Indy cars and formula 1 race cars are built out of very lightweight carbon fiber and are designed to shed parts to absorb and dissipate the force of a 200+ mph crash and allow the driver to walk away.
Vehicles can easily be repaired or replaced, people are a different story.

 

Fair enough. For most of us the vintage vehicles are a far cry from carbon fiber technology and "crash tested" I get that and your points are taken.

As to your point, rigid structures can transfer much of the force to the occupants.....
For anyone doing IFS I think we all agree that it is essential to have a boxed front clip and that's somewhat a universal truth for trucks of this model.

So can we work towards the back of the truck from there?
I like the idea of a perimeter chassis for multiple reasons, so let's say we do a perimeter frame in the cab area and go back from there. I agree that if in an impact total rigidity in this area can also have negative consequences. To me that is one of the attractions of NLE's 10" X braced C channel in that area (I know race cars & new cars use different materials but those really aren't options for our trucks). That large C channel may actually absorb more impact than what the mandrel bent square channel from AME. I would like to hear opinions on this from anyone with some

AXracer if I understand you correctly, then you are not a fan of the trailing arm suspension that NLE is promoting....so for sake of discussion let's remove that from their frame as I would like to discuss the rear 1/3 of their chassis. NLE's chassis becomes what appears to be 1 1/2" or so square tube stock as it passes over the rear axle. When considering their design it seems to me that this would actually work as a "crumple zone" and absorb some of the energy from a potential rear end collision. What do you guys think?

Not that it matters much for this topic, but I've spent a fair number of days on the track at Willow Springs, Streets of Willow, Buttonwillow, Laguna Seca and a few other West Coast tracks. I've even had the privilege to drive in a couple of US Presidential Motorcades....so I get defensive driving

What I haven't nailed down is the best configuration of chassis design & components for what I want to do.

 

Since you asked nicely I'll try to answer your questions the same way. please read my answers carefully and with an open mind.

The fact is for an IFS of the M2 design for street use requires only about 10" of boxing centered on the crossmember because to allow for control arms of adequate length needed to keep the camber gain under control and the tires under the fenders the pivots need to be about centered on the frame rails so the crossmember needs to mount on the inside of the frame. The forces on the upper spring mount want to bend the unsupported side of the upper flanges down, so the boxing is required to resist that force and give adequate surface to weld the crossmember to. If you search and look at the pictures of a GMQ/CV IFS install, the aluminum crossmember is bolted vertically thru the frame so many use round tubing spacers to support the upper flange. Any additional boxing is for a cleaner appearance rather than structural necessity. A lot of builders box from the front crossmember back to the firewall again primarily for esthetics rather than structure. The 2x6 C channel of the OEM frame is plenty strong enough for street use. it's the flat ladder configuration and minimal riveted crossmembers that gives the flexibility, the rails themselves do not appreciably flex.
Adding depth to the rails like the NLE design with the same width flanges and metal thickness as the OEM rails does not add significant torsional strength or side impact strength. Adding a similar X or K member to the stock frame would make it nearly as ridged at the NLE under all but the most extreme racing stresses. Note that in the NLE videos their truck also has a tubing stiffening structure in the bed from mid roll cage to the rear of the frame similar to a NASCAR truck series or NHRA Pro Street truck.
I am not fond of the reduction in structure size after the rear axle reducing the rear impact strength in the area of the gas tank. Shades of the Pinto!
Clarification: the trailing arm rear suspension is an adequate simple rear suspension that allows room for the massive X member for street and drag racing. It is the required suspension used by NASCAR (it is easily inspected for unauthorized "modifications") but if you watch the NASCAR cars on the road courses it is not well suited for road racing (or autocross) handling. There are much lower powered cars with more sophisticated rear suspensions (i.e. IRS and/or multilink) that turn much faster laps at those tracks (the courses are also modified to bypass the tightest turns for the NASCAR races).
If I was specing a chassis to meet your requirements (and my own vision) without regards for cost I would order a AME F100 truck chassis with semi loops of 2x4 rect tubing "outriggers" under the cab to provide your extra side impact strength, with their "sport IFS" and their multilink IRS with double adjustable shocks all around. A lower cost but nearly as good second choice street/handling chassis would be the same frame as above with their AME/Wilwood spindle IFS and triamgulated 4 link solid rear axle with rebound only single adjustable coilover shocks.
My opinion is based on what I believe would be the best bang for the buck replacement chassis available without any prejudice or agenda.

 

BTW: you do know that the stock frame sides are only ~10 - 12" inside cab footprint?

 

I know nothing about aftermarket frames, and I know even less about aftermaket suspensions, and this thread had had a lot of reading.


If I was concerned about the frame rail to edge of cab position I would simply put another set of front cab mount outriggers towards the rear of the cab, connect the newly mounted cab outriggers to the front cab outriggers and make hidden Knerf bars.

 

Thanks for the insightful post on a upgrading a chassis AXracer. Some good points...For one, I hadn't considered adapting "Outriggers" in the cab area and that may be an option.

Here's some illustrations on the stock chassis & the stock gas tank measurements. In those narrow cabs, 12" of little more than sheet metal certainly wouldn't absorb very much if impacted. For me, I will feel better about having the cab perimeter beefed up a bit....and pray that it's never needed.
Thanks for your input.




1953-55 Ford F100 stock chassis





1953-55 Ford F100 stock chassis





1953-55 Ford F100 stock gas tank measurements

 

Ford already installed a set of pretty sturdy nerf bars, We just usually call them running boards!

If concerned about the gas tank location, Many relocate a tank between the rails under the bed, or you could use a panel truck tank that mounts inside the rails.

Actually I don't recall there ever being a lot of concern about or reports of excessive injuries or gas fires from side impacts in the 50's era Ford trucks.

 

If occupant safety and chassis rigidity was my ultimate concern, then I would simply put in a well designed roll bar or cage. Would add most stiffness better than any chassis design short of a full tubular NASCAR design, Would add more/better occupant protection from side impact, rollover protection, and ease of properly mounting 3 point seatbelt/harness.

 

Have you considered looking at doing the Mustang II or Dakota front suspension with a Thunderbird IRS?

Team321 LLC Ford Truck Independent Rear Suspension (321)960-5945 dheld@cfl.rr.com

I know that OkieDokie put one of the Thunderbird IRS setups in his '53.

Even with these F100s sitting low, the passenger seating is relatively high. I do question the effectiveness of the perimeter chassis. I would think, however, if you chose to build some tubular side riggers and adding some tubular crossmembers between the frame rails, you could achieve the same result.

 

That looks like an interesting and viable way to install an IRS onto a stock frame.
Q: Do you know if there is still room for a rear mounted gas tank with this configuration? (Or does the rear cross-member need to be repositioned?)
Thanks for the info

 

Apparently Lee Iaccoca said "Safety doesn't sell".....and here we are in 2014 and if you don't bubble wrap your kids before they step outside the home, then there are plenty of lawyers lined up to blame the parent.
So, since the 1970's America has transformed into a country where "Safety does sell"....and that is why so many families would rather put little Jimmy in a Prius than a vintage car....and Jimmy never knows what he has missed out on.

You are right, I haven't ever heard about the side mounted saddlebag gas tank being reported as an issue...but I also didn't know that there was another 500+ reports of people getting burned by Pintos...as before 1965 I believe most people just said "Crap! Johnny got in a bad accident & during the accident the car caught on fire"....and then they went on with living life regardless of how bad the outcome may have been. Then according to this article Pinto Madness | Mother Jones Mr. Arjay Miller's Lincoln Continental caught on fire and he started challenging some of Ford Motors gas tanks & designs (If you can't tell, I like to read a lot).

So, while I'm not one to bubblewrap my kids, I am a person that is willing to take a little bit of time trying to figure out how to build a truck that has a few additional safety features built into it. I don't have any plans to incorporate a full roll cage, but I am considering designing a lower partial cage that would provide some better options for mounting shoulder harnesses and provide some additional support.

Given my plan to use a modern suspension (IFS up front & possibly IRS out back), any thoughts on directly mounting the cab to the frame as opposed to the factory shackle mounts?
Does anyone have experience with this?
What would be the best dampening agent to reduce potential noise transference from the frame to the cab? (Besides Dynomat type liners) I'm specifically asking about between the frame & the cab.

 

Dunno the answer on that one. You might want to reach out to daveheld, here on the FTE site, or send him an e-mail and ask that question.

My thought was that it's another viable alternative to achieve your goal to make the truck handle well, with fairly minimal intrusion to it's existing chassis (and your wallet!)

 

Just so you all know, It's me. Rob, from No Limit Eng. I have enjoyed the topics here, and maybe I can clear a few things up. There are a lot of reasons why we switched from a standard ladder frame (that we built for many years, called a Pro-Tech Chassis) to the Big-10. Performance and safety were key points in that decision. Performance can be many things to many people, and everyone would define it a little differently. Having a rigid platform can help in many ways. While the most talked about here is the ability of the suspension to do it's job without the chassis flexing, there are other benefits. Having a chassis that is more rigid will allow the doors to stay in alignment, and also the hood and front fenders. How would that be, an F100 that has the door shut nice every time. Or, one where the hood fits every time. In addition, Having the cab stay still keeps the sheet metal from "oil-canning" as you drive, which leads to more in cab noise. Eliminating this noise and shifting around of the sheet metal gives the driver a better experience, and that is one part of the driving performance.
Many other things have been brought up in this thread, and I'll give some information on a few.
Our Wide-Ride IFS uses a modified Impalla based spindle, we have them custom made, not an MII. The front brake that comes with this is a 12" drilled and slotted rotor with a full size GM caliper.
Having the rear suspension 'divorced' via the rocker arm allows something that no one else can do. In a traditional coil-over set up, ride height and shock 'squish' is in the same set of mounts. So, if you set shock squish at RH at 50% of travel, the ride height is whatever it is. If you set the ride height right where you want it, the shock squish ends up where-ever, and may not be optimal. In our rocker arm set up, shock squish is set on the coil-over and the ride height is set with the up-link.

 

This is a 96 Mark VIII mounted in a 55 ford panel. I notched it up and in so to lower the panel. As you can see no room for a rear tank, I moved my tank to the driver side running board arm, same as stock 55 pick-up. In the one team 321 shows with the brackets might get a very small tank in but I would say no