roll bar main hoop mounting with a narrow frame

i have only installed one cage, and that was a camaro. in a camaro, you bend some plates to the shape of the floorpan right around the stamped frame rails, and weld your hoop in.

now i'm dealing with something old. it has narrow(33" apart) frame rails, and the main hoop would be mounting about 11" outboard of them. the floor does not exist yet, nor do body mounts. i'm in process of that. i am leary of mounting to the floor so far away from the frame in fear of, if i did end up on my lid, the plates could punch through or at least deform the floor enough that i would be in danger.

i had a thought, to build a structure that included the body mounts behind the front seat(2 door, 2 seat car, no need to worry about rear passengers) out of 2x3 or 2x4 tube as i have lots of it available, that would also include a mount for the hoop. the frame kicks up in this location and i was planning to kick the floor up behind the seat anyway to make a straight floor right through the trunk to the tail panel anyway. i figure a 6" kick up would get me straight through and make the floor fabrication easier. if i made that 6" tall by x" wide kick up/body mount/hoop mount combo out of 2x3 or 2x4 1.25 rectangle tube, would that fly as a proper hoop mounting point or would i be turned away in a tech situation such as in gainesville in october?

the other thing this would aid is the fact that i have a hoop for another car, that cost me $0, so - you know - no budget hit if said car were to come to gainesville in october for a certain event. it's 6" short of the headliner right now. width is perfect. they do not make a hoop for my particular car so i would have to go have summit bring out some random ones that might work and measure them, or have one made. being able to use what is on hand would help.

i can draw my idea if necessary.

Mount it to the floor as close to the outer edge of the floor as possible. Carry the mounting plates up onto the outside vertical sides. SCCA allows 144 square inches of mounting plate. Use it all if you have to. The only car I ever build a cage in where I was worried about the floor was on an old VW Beetle. I cut out the heater boxes and ran 2X2 square stock in it's place all the way around the perimeter of the floor pan. Sat the cage feet next to and up on top of the 2X2. Then I carried the cage forward to the front beam and rearward to the frame beside the engine.

In reply to patgizz:

On a body on frame car where the frame is narrower than the body width (like a pickup or your Business Coupe) you need outriggers from the frame out toward the rockers then the cage is tied into them.

You might want to poke around on Streetrodder's website and check out project RamRodder. It has some things in common with what you are doing.

RamRodder Cage Article

Big plates and stitch the hoop to the body at intervals as well.

yeah that's pretty much exactly what i'm doing. same car even. but i'm only going 8 point bar for now.

think i'll go measure up a camaro main hoop that is uncut, as the cut one would be perfect if it were about 6" longer, and i remember when i caged the camaro i had to cut at least that much off the hoop when i fit it. i can't start on it yet because i need to lift the body off one more time when i get my mounts tacked to the frame, so i can finish weld, paint, and generally make the frame pretty

patgizz wrote: yeah that's pretty much exactly what i'm doing. same car even.

Yep that's why I recommended it.