Hi guys,
Since I'm one of the few who've actually survived by the use of properly mounted seat belts, I feel qualified to chime in
My belts are 5-point.
Two points are the normal lap belt anchors adjacent to each side of the seat.
One point is the crotch belt anchored just under the front of the seat cushion.
Two points are the Y-shaped shoulder straps which come together just behind the seat - very, very close behind the seat top, and exit through the bulkhead directly behind the seat, slightly below the level of the top of the seat. The single strap is anchored inside the trunk to the base of the roll bar, several inches below and to the rear of the level of the opening.
To pass the single strap through the bulkhead, I use a "letter slot" opening with an aluminum Factory Five bezel on the front side. The slot is centered behind the seat top, slightly below the seat top and is wide enough to allow the rearward portion of the "Y" to go into it.
About 1-1/2 years ago my instructor Cliff and I left Turn 3 at Summit Point race track at somewhere over 100 mph, hit a berm and flipped. Hard. Except for my left arm (see tag line below) neither of us got a scratch.
The roll bars (double hairpin style), the helmets and the belts did their jobs.
The belts were anchored in accordance with Simpson's instruction sheet that came with them.
If you're gonna drive hard, put the belts in like they're supposed to be put in!
Questions?
Tom