Here is a pic of the car from the Jack Tuned youtube channel. Does the part I circled satisfy 2B requirement for a 25.5? Also you can see how he has #1 behind the main hoop and they made him add a gusset with this arrangement and he has a boxed frame for #7 bar? If you look at the pic of my frame on chassis table above you can see where the old main hoop attached to the frame and I plan to put the new one in the same place which will be closer to the B pillar than the Cutlass. If I run #1 bar under the floor pan it will be in the same location he has it on the Cutlass.

 

Really nice work on the 25.3. Did you end up having to gusset the #10 to #1 bar like Jack Tuned? I’m doing a box frame #7 bar on my GN with #10 and #12 welded to frame

 

This is how I am planning to run the 51B bars on mine except they will be prostreet style and go along the roof line down through the speaker deck and attach to the upper coil over brace. Does this also satisify 25.3 or will I need the x-brace too? The spec seems to read the same for both except maybe 2B has to extend to meet 51B on 25.3?

 

I cant personally answer your questions, but may lead you to a bit of help. Being you have a GN, Im assuming you have found the fellow that goes by "Reckless Regal" on youtube? If not, check him out...its a 25.3 build & for a guy in his garage, pretty darn impressive! He seems to have slowed as of late (which is a bummer, I looked forward to the new content) but life gets in the way at times. Lorne

 

Hey man. I can't answer any of your questions. But I am doing a gn build with an old tso car that the chassis has been updated. V6 ta motor I put together going to run a dominator on it. I'm right outside of Cleveland. Would love to talk to you about your setup maybe get some advice. If you have time.

 

Sure thing I sent you a PM with my number. Whose car did you buy I may know the car? I ran the TSO point series up through 2010 and raced the class for a bunch of years.

 

Just trying to go low 8s hopefully going to put an 88 on mine as well

 

I have checked out the Reckless Regal and he has some good stuff I just can't stand the music he plays lol!

If I was tearing out the floor and complete back half the issues I am dealing with are easily explained in the SFI spec books. Trying to keep as much factory sheetmetal and interior to make it look like an actual GN is more difficult.

I reached out to a couple of NHRA chassis inspectors via email but haven't heard anything yet.

 

Here is a pic of the rear rail in the 25.3 chassis I built but ended up selling. The chassis inspector made us add this rail to get the 25.3 spec but it does not talk about it anywhere in the manual and I have both SFI spec books. I have tried reaching out to two NHRA chassis inspectors and have not gotten any response.

I am trying to figure out how to lay this out now before I start running floor bars which I hope to do this week. I would like to take 2B inner rail from #1 main crossmember up to the bottom of the Merilatt crossmember and from the top of the Merilatt crossmember to the upper coil over bar where 51B down bars will mount. The 2nd pic is from a Malibu I found in a for sale ad on FB. I intend to run similar this pic in which he has 4 crossmember #1, Merilatt then a Coil over mount to tie 51B to and a fourth one behind the rear tire to stiff rear frame after the wheel notch. I know it will meet 25.5 but not sure 2B can be interrupted by crossmember and be 25.3 compliant?

Only issue I see is the bottom of the Merilatt x-member is 1.25 and the top is 1.5 and the 2B bar spec is 1.5" .065 wall CM. Not sure what Merilatt used

Any help is appreciated

 

Well the NHRA chassis inspector called me back today and answered a lot of my questions so I thought I would share some of that wisdom here in case some one else goes looking for the info in the future.

Generally on a full frame car the factory rear frame rail serves as the 2B bar and a second inner rail is not required. UNLESS you cut the frame notch all the way to the inner rail without plating and boxing the rear side. The NHRA tech said he would not have passed the Ron Burgundy car without a second inner rail. That is also why I had to add one to the 25.3 chassis I did years ago because we did same thing and inner rail was very thin. On the frame on the car I am doing now he said there is enough material there and he would pass it even for 25.3, see pic.

I did ask him about running an inner rail to the bottom of the Merilatt crossmember and from the top of the cross member then over to the coil over mount like the pic I posted of the For Sale Mailibu I posted in my previous post. He said he would pass it like that with the x-member intersecting the 2B bar.

IMO Merilatt should consider making that bottom bar 1.5" then I dont think there would be any question.

 

Done and got my 25.3 tag! It was a journey and real learning experience! I did get a lot of feedback from the NHRA tech inspector on the build the whole way through which was really helpful. This was a two man job with both of us watching youtube videos in April learning how to turn on the TIG welder and put the tubing bender together!! I did all the tube prep, bending and coping and my buddy Ray did all the welding and he had gotten amazingly good at it in a really short period of time!

 

Awesome work! I am in the middle of a 25.3 in my K10 as we speak. I started a build post in hopes folks would get behind it but it hasn't gotten much attention it seems. I need to go back through and read again, but was was the reason for having to add the inner rails?

 

Thanks! It was a lot of work, I looked and we started welding on the frame on July 1, 2022 so pretty much 6 months working on it nights and weekends. FB killed the forums and I hate FB. This place used to have a ton of cool info on it and build threads to follow which I enjoyed, as you can see my question did not get a lot of attention either

The SFI spec book isn't real specific about the 2b bar and how it is supposed to be run and my original question pertained mostly to that. I had seen several builds without them and some with and then since I had an aftermarket crossmember how I would have to run it. If you have a full frame and your frame notch in the rear is still a boxed frame rail they will accept that as the 2b bar. If you cut your frame down to the inner rail and have just a thin piece of metal there like most do then you would need to add the 2b inner rail in the rearend. In the pic the red line would be the 2b bar I would have had to add if I cut my frame notch deeper but since I have at least an 1" of boxed frame rail still he accepted that as a 2b bar.

There are a few other details I learned, like the diagram in the book for the roof x-brace is WRONG and you need to go by what is written. The roof X brace does not have to be an exact X or follow the rules for an x-brace that they require for door diaganols and the floor x-brace. That will probably matter to you since you dont have a lot of roof area.

Also, get your 2nd door diagonal as close to the bend and dash bar as possible, if it is to far away they may not pass it for a 6.50 cert, that was something new this year. Mine is not in the center of the bend but at the start of the bend which was enough to satisfy the spec requirement.

Good luck on the build I will check when you make updates!

 

If thats the case it will put my 16B and 17B running through the dash.

 

It was something he told me about. They want to see that bar as close to the bend and the book isn't specific on it. I am not sure if it is something will be in a future update and is only for the heavy 6.50 cert and not the 25.5 cert.

That looks as long as it doesn't make getting in and out a PIA. Have a plan to weld that 16b bar 360* along with the two gussets. We had to raise the body and go through the hole for the door wiring in the cowl! We used bendable tungsten on the gussets.

 

Put the dash bar in yesterday. Not going to run it that high (in the picture with the tape) too much of a pain in the butt. I would have to lower the truck just to get out if I ran it up that high.