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You mean a roll bar and not a roll cage. If you just want the 5 point belts you don't need a roll bar, but if you are going to really USE 5-point belts than you DO need a roll bar. :)

If I was going to bolt it in it would be on to reinforcement plates welded to the floor, wheel tub and roof inner structure and secured with oversized flange-head bolts and lock nuts.
 

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If all you’re concerned with is cosmetics, a bolt in will be fine. It you’re looking at something functional, weld it in.
 

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1965 Mustang Fastback GT350-Tribute Restomod. 2019 Shelby GT350.
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I had a bolt-in roll cage fabricated using welded floor plates. We have provisions for conversion to a 5-point bar, but I don't think I'll be fast enough to legally need it.
 

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If all you’re concerned with is cosmetics, a bolt in will be fine. It you’re looking at something functional, weld it in.
I understand.
But bolting in is something I can do myself vs finding someone who can weld it for me.
Maybe just duct tape it in then if you’re doing this only based on what you’re able to do yourself, vs doing it the best way. :wink:
 

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tl;dr = that car didn't have a cage, it was a roll bar and under the proper rules and design you can run a bolt in cage safely.

The pics of the crash look like a roll bar and not a cage. A cage will fully encompass the cockpit with not only a rear hoop and kickers but a roof halo, A pillar bars and some sort of door bar. There would be at least six points of contact if not eight or ten. It also wasn't big enough for that weight of car. To meet SCCA or NASA regs that car would need a full cage of 1.75 x .120 DOM for the weight of the car. (Appendix I, 9.4.6 Production Roll cage)

Even with that roll bar welded in it's not likely it would have survived an endo like that. Backing plates to bottom of the structure could have helped but it looks like it was lack of overall structure and not just the uprights poking through. The entire load went to those two points on impact. In fact the off road orgs (SCORE and BITD) don't allow for welding footing plates to body steel. They have to terminate with a weld into the tube chassis or ladder type frame rail or be attached bolted through the body sheet metal to a backing plate and the area of the plates is determined by the weight of the vehicle. In SCCA you can use a bolt in cage (with backing plates) in some classes as long as it passes tech with regards to the other design considerations. That GT is one of those classes. For production car bodies the NHRA also does not allow welding to the body sheet metal. You must use 6" x 6" footers with same size backing plates bolted through. For the SCCA and local Nascar classes I've built cages for we do weld into the body sheet metal (floor) but we are bound to minimum areas on those footer plates as well as minimum thicknesses. With the Mustang mostly done I'm starting cage fab on the SCORE spec Ranger that will be bolt through at four cab points, welded to the frame in ten other places.

Here's a minimum cage diagram from the SCCA GCR for the class that GT would have run.

 

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tl;dr = that car didn't have a cage, it was a roll bar and under the proper rules and design you can run a bolt in cage safely.

The pics of the crash look like a roll bar and not a cage. A cage will fully encompass the cockpit with not only a rear hoop and kickers but a roof halo, A pillar bars and some sort of door bar. There would be at least six points of contact if not eight or ten. It also wasn't big enough for that weight of car. To meet SCCA or NASA regs that car would need a full cage of 1.75 x .120 DOM for the weight of the car. (Appendix I, 9.4.6 Production Roll cage)

Even with that roll bar welded in it's not likely it would have survived an endo like that. Backing plates to bottom of the structure could have helped but it looks like it was lack of overall structure and not just the uprights poking through. The entire load went to those two points on impact. In fact the off road orgs (SCORE and BITD) don't allow for welding footing plates to body steel. They have to terminate with a weld into the tube chassis or ladder type frame rail or be attached bolted through the body sheet metal to a backing plate and the area of the plates is determined by the weight of the vehicle. In SCCA you can use a bolt in cage (with backing plates) in some classes as long as it passes tech with regards to the other design considerations. That GT is one of those classes. For production car bodies the NHRA also does not allow welding to the body sheet metal. You must use 6" x 6" footers with same size backing plates bolted through. For the SCCA and local Nascar classes I've built cages for we do weld into the body sheet metal (floor) but we are bound to minimum areas on those footer plates as well as minimum thicknesses. With the Mustang mostly done I'm starting cage fab on the SCORE spec Ranger that will be bolt through at four cab points, welded to the frame in ten other places.

Here's a minimum cage diagram from the SCCA GCR for the class that GT would have run.

I know the difference between a rollbar and a cage. I could also read between the lines so far what the OP is trying to do ;)

Still not a fan.
 

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Bolt in bars are just a false sense of security. Jherrod's method is the best way to go if being able to remove the bar is required.

For not much more than the $650 they want for that bar, you can buy a CE 8 point kit and have a local fabricator that does this type of work weld it in. It'll stiffen the car and provide real protection. If you don't want the door bars, then don't use them. You also need to set up the main hoop position to the driver, as the bar, belts and seat have to be positioned specifically for you.

https://www.summitracing.com/parts/cee-3039-k/overview/year/1970/make/ford/model/mustang
 

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thanks for the thorough explanation. Very helpful.
Yes, roll bar is what I’m looking for. Not cage.
You're welcome. :smile2: The Autopower line you're looking at is what those I've seen doing sports car track day cars or lower cost race cars were doing. I'd still use backing plates and if possible get the model with the single bar forward on the driver side. That makes it more of a pain but having at least kickers on both sides will help if the bar wants to fold forward.

I'm as tall as you but I can't offer anything on the seats for a car that's going to be driven on the street too. Our mounting was different, the seats had restrictive head containment features, features and an application not at all for the street. Trying them is difficult for most. Around here when the big off road races come through at tech there are plenty of vendors a few of which have the various seats they offer on display to sit and try. I bought my first couple of seats sight unseen based on what others were using at the track. If they have SCCA or NASA events in your area you can swing by and check out what others are using. If you go to an NHRA event and stop at the Sparco/Mastercraft truck in the fan zone they usually have a few seats out to try plus helmets, suits, shoes, head and neck restraints, pretty much everything.
 

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WOW, the price on those has really gone up!
Just call it a harness bar to keep the high horse brigade in check. Everyone pulls out those Mustang pics when a bolt-in bar is mentioned but in that extreme case a double plate welded in those same floor spots would not have helped in my mind. Maybe self-tappers with it atop the torque box though.
For anything more than a harness bar I would want it on the torque box and the legs back down to the frame rails, not the wheel wells. jherrud has a good idea going on with the hard points


I couldn't swipe this pic, https://rennlist.com/forums/993-forum/939953-bolt-in-roll-bars-vs-welded-in-bars.html
There are many more helpful examples of both bolt-in and bolt together options, its all about execution.
BAD DAY: 180SX crash and flip at Bihoku : NORIYARO
 

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Discussion Starter #15
The autopower kit will meet my requirements and seems like the best choice for me.
Yes, welded mounting plates would be a good idea. And I may consider adding side bars.
I’ll lookup one of the local off-road builders to see what they can offer for comparison.
Thanks
 

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I was with you for bolt-in till you get to more than a simple bar. When thinking about how much these cars will move flex and dent with moderate forces, meaning what would just be a hard but harmless fender bender in a modern car, i wouldn't want anything else besides a rigid welded and modestly triangulated something something. Anything by the doors will make any incident worse unless it was built to the 11's. If you're going to need a bar and a 4-5 point belt, spend on a HANS next.
 

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===== I posted this over in the SVRA thread as well, excuse the cross post=====

I just saw these guys out at track at a drag event.

RPM Rollbar

Very clean looking cages and roll bars. They had a couple of demo cars that were also running and a good number of the late model Mopars and others were running the 6 pt cage or roll bar. I saw the gamut of Mopar options, late 60s to now and several late model Mustang GT stocks and mod stock. Several of them were IHRA or NHRA tagged cars. The product is NHRA, NASA and SCCA legal. If your cage doesn't pass tech they'll buy it back. Welded joints but fully user installed and removable without welding. The swing out door bars are a nice touch. Available in DOM or 4130. Very impressive. Fairly expensive. The company isn't 10 years old yet but the guy who owns it is a well known drag car fabricator with about 20 years experience.
 

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I used the Jegster kit. It's inexpensive and designed as a bolt in kit but requires minor welding. I have it welded to the inner wheel wells and also my subframe connectors through the floor. For the price you can't beat it, I'd make friends with a welder!
 
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