I can't download the 2011 rule book so I'm just gonna post the question here like a noob instead. What does FD require for the base plates that you weld your cages to. Material and thickness.

Also, i noticed some people welding up plates into boxes and using the tops as the base plate. Whats the advantage or reason for this? Thanks in advance

 

https://www.rx7club.com/race-car-tech-103/scca-role-bar-requirements-628359/

I did some research; I think it has the answer. I would think that "going with what you feel" could work; if you thought like a FD rule book creator.

 

Do a lot of racing associations go hand in hand with rules?(for the most part)

Quote from "wlfpkrcn" from the link I provided about NASA ruling on plates for welded and bolt-on cages; thank him...

15.6.14 Mounting Plates
Each mounting plate shall be no greater than one hundred (100) square inches and no
greater than twelve (12) inches or less than two (2) inches on a side. Welded mounting
plates shall be at least 0.080-inch thick. Plates may extend onto vertical sections of the
structure. Any mounting plate may be multi-angled, but shall not exceed one hundred
(100) square inches total including vertical sections. Each mounting plate should have
an area of not less than nine (9) square inches.
61
15.6.14.A Mounting Plates – Bolt-In Cage
The attaching points of a bolt-in cage to the body must use reinforcing plates to
sandwich the body. At least three (3) bolts are required for each bolt-in plate and the
plate must be at least 3/16 inch thick. All hardware must be SAE Grade 5 or better with
5/16” diameter minimum. All nuts must be held securely by a locking system such as
safety wire, lock washer, Ny-lox, or jam-nuts.
15.6.14.B Tube / Mounting Plate Specifications
Any number of tubes may attach to a plate so long as they are touching each other at
the plate. There may be a small gap between tubes to allow welding 360 degrees
around each tube. If there is no gap between the tubes, they must be welded around
the base as much as possible to form a single figure-eight weld, AND the tubes must be
welded to each other two (2) inches up from the base plate.
15.6.15 Welds[/QUOTE]