Introduction-

Due to the desire to run in the excess of 8.50 et’s with speeds of over 160mph, the Fordmuscle Ranchero will need a chassis that is up to the task and safe.  2011 will be when I bump up the POWER! I first began by removing engine, trans, wiring, fuel cell and all peripherals . I cut out the old roll cage. I quickly realized the sawzall will be my best friend for awhile. I now will get another chance to do things right, which I should have done in 1999.  The class I am building this for requires a stock (type) front suspension which includes and allows the MII modification I already have in place. So, the chromoly tube chassis will be bulk headed into the stock front frame rails.

If you wanna go Fast…You Gotta be Safe!

Here is some information on SFI  Safety & Chassis Classifications.

In 2003 The SFI Foundation released four new specifications designed specifically
for the roll-cage design on full-bodied cars. The specifications contain requirements
that will affect at least some of the cars that compete in NHRA events
(national, divisional, sport compact, and local series) and the events of alternative
sanctioning bodies. The significant new and/or modified requirements are noted below:

What Does SFI stand for?
SFI was originally a foundation run by SEMA, the automotive aftermarket trade organization. The letters “SFI” stood for “SEMA Foundation, Inc.” Although SFI is now completely independent from SEMA, the Foundation has retained the name SFI Foundation, Inc. but the “S” no longer means SEMA.

Visit the SFI website for more info: SFI Web Site

SFI 25.1E
Application: Pro Stock-type tube-chassis roll cage; 7.49 seconds and quicker; 2,800-pound maximum Implementation date: on all new chassis or next scheduled recertification, beginning Jan. 1, 2004 SFI Spec 25.1E is an updated revision to the current SFI Spec 25.1D with a few small modifications.

The new spec limits the maximum total ballast to 250 pounds and implements minimum bolt and tab/mount requirements. The spec also provides the interpretation for the 2,800-pound maximum weight requirement. The other change is the addition of a 1 1/4-inch driver-side kidney bar that has been added in three of the four roll-cage configurations.

SFI 25.2
Application: Pro Stock-type tube chassis roll cage; 6.00 to 7.49 seconds; 3,200-pound maximum
Implementation date: on all new chassis or next scheduled recertification, beginning Jan. 1, 2004
SFI Spec 25.2 primarily affects cars that compete with alternative sanctioning bodies. The SFI 25.2 roll cage contains several upgraded components in the floor, roof, sides, and dash. These specifications were developed so that an SFI 25.1D roll cage may be upgraded by replacing several components of one-inch outside diameter (OD) or less with larger components and adding some new components in order to retain some of the other components that are larger than one-inch OD.

SFI 25.4
Application: Pro Stock-type mild-steel or chromoly tube-chassis roll cage; 7.50 to 8.49 seconds; 180.00 mph or faster; 3,600-pound maximum Implementation date: on all new chassis or next scheduled recertification, beginning Jan. 1, 2005
This specification will affect many of the slower full-bodied cars in Comp, E.T. cars, and those that compete with alternative sanctioning bodies. The specification is quite similar to SFI 25.1D with a mild-steel option for the material. The sizes of some components are slightly downsized from SFI 25.1D. It also permits rectangular
tubing for the floor components. The major changes are the Funny Car cage, floor, and cage-support requirements.

SFI 25.5
Application: mild steel or chromoly; full-bodied car, stock or modified/OEM floor pan and firewall with OEM frame or uni-body construction; 7.50 to 8.49 seconds; 180.00 mph or faster; 3,600-pound maximum
Implementation date: on all new chassis or next scheduled recertification, beginning Jan. 1, 2005
This specification will affect some of the slower full-bodied cars in Comp, some cars in Super Stock, many E.T. cars, and those that compete with alternative sanctioning bodies. This specification is quite complex but is similar to how SFI 25.1D has been executed for many of the cars in alternative sanctioning bodies that require an OEM floor, firewall, etc. The spec has a mild-steel option for the material, and it permits rectangular tubing for the floor components.

The sizes of some components are slightly downsized from SFI 25.1D. Based on retention of OEM floors, rockers, firewall, etc., some of the SFI 25.1D components are not required. Other major changes are the Funny Car cage, floor, and cage-support requirements.
Fire system requirements for 2004: Beginning with the 2004 season, all nitro Funny Car and Top Fuel applications where the driver sits behind the engine (nostalgia) and on rear-engine cars with an enclosed cockpit will be required to have a fire-extinguisher system that meets SFI Spec 17.1.

NHRA and SFI Foundation implemented this program to develop guidelines for all of the available systems and to set uniform test procedures and minimum standards for evaluating and determining performance capabilities for systems designed specifically for a drag racing application. For 2005, all additional vehicles that are required to have a fire-extinguisher system must meet SFI Spec 17.1.

Revision to SFI Spec 2.3K: As a result of recent field experience, SFI Foundation has determined that the use of a single back brace in SFI Spec 2.3K will not be permitted on cars built after Jan. 1, 2004. Beginning with that date, all SFI 2.3K vehicles are required to be of a two-back-brace-support design. The specification amendment, which impacts dragsters in Top Fuel and Top Alcohol Dragster, affects all cars built after Jan. 1, 2004, and all existing cars at the next scheduled chassis recertification. For information regarding SFI Spec

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