andrewmp6

Your thinking about a 4 point cage I'm talking about a Shelby style roll bar like this http://www.cobranda.com/19shpacoroba.html and its padded.

120mm

So you want to put your three point on a repro "decorative" roll bar?

There are two things terminally stupid about this. First, no amount of "padding" will stop a roll bar from crushing your skull. (Unless you are wearing a helmet). Second, that "roll bar" is a decoration. You know, like a bobble head is a decoration. Upon front impact, that thing will snap off and join you in the front seat, at high velocity.

I'm thinking the best solution is to give up the back seat and move the (real) roll bar out of whiplash range and get a really good high back seat to boot. I want to keep my top, so I'd like to look at the geometry.

I'm also still wondering about anchoring it in the trunk. Anyone have a 3d modelling program that will show what will happen with a 3 point in that position?

andrewmp6

They put its for decorative for legal reasons its a copy of the same bar Shelby put in his convertibles.The bar itself is welded in its no weaker then the rest of the cars unibody.

clowe1965

I don't think you need a 3d program to do that. Look at the location/angle of the belts in the newer mustang coupes and convertibles. Not exactly right above the shoulder. While i agree about bashing your head on the roll bar, mounting a 3 pt seatbelt to a roll bar will let it function fine.

120mm

Hmmm... I was wondering how strong the single bar is, mounted like that. One would think it could be improved with a transversal. I'm still seeing not a lot of strength there.

clowe1965

You are talking about a seatbelt, so not a lot of force compared to what the rest of the car sees during a crash. Now a single bar, not a four point cage, I would not recommend as a connection point. Not without some additional bracing. The bar would possibly bend, causing more damage to the floorboards and creating a greater risk of bashing your head against it when you get snatched back into the seat. Sorry for the confusion, i only remembered the 4 points, forgot about the decorative roll bar they sell.

Fyi i can model and simulate the stress in the rollbar if anyone is interested.

Diputado

OK, folks...the seat belt kit arrived yesterday. I haven't had time to fully "digest" the instructions that came with it, but for 64-67 coupes and all convertibles it indicates an anchor point through the metal panel just below the rear window and just behind the door jamb. In the installation kit, there is a steel base plate with a 1/2" bolt that is supposed to protude from the hole that you need to drill for this purpose. Seems a little low, to me. BUT...for 68-73 coupes it uses an "existing" roof mount (apparently those mdoels came with factory 3-point belts). For the other anchor points, it simply uses the factory 2-point sites. Also...if you looked at the video clip that someone in this forum attached, they also fabricated a roof-type anchor point in a 67, although that took a bit of cutting and welding. Like I said..I need to ponder it a bit...but the kit looks fairly complete in terms of hardware and all. The illustrations suck, though, and are at times contradictory to the written instructions. I think I'll drop by one of the local body shops here and get an additonal opinion on this setup from someone who does sheetmetal work for a living! Getting there...!!!

fastbackford351

My 67 already had the mounting point in the roof for the shoulder belt.

Post up pics of this project. I'd like to see how it works out.

120mm

That's exactly what I thought. A single bar will at the very least bend, causing the issues you mention.

I am starting to consider actually doing something like a 6 or 8 point, with a five point harness and a really good seat. I'm "stuck" with a convertible, but want more performance than a stock body will give me, and am wondering if better seatbelts plus a solid seat will keep the head from impacting the roll bar upon impact.

120mm

So - I will admit to being a complete idiot here. I was stuck in "the box" of roll bar or no roll bar.

If you want to put a 3-, 4- or 5-point harness in a convertible mustang, you could actually run a stub 4 point roll bar that runs the entire width of the car, but terminates at the height of the shoulders. This would retain esthetics, but avoid being located next to the head. It would also help to anchor the seat-back to it, as well as the harness.

When I quit thinking of it as a roll bar and started thinking of it as a shoulder belt mounting point, it helped pull my head out of my fourth point of contact on this issue.