Hi guys
I am intending to install bolt-on sub frame connectors on a 69 vert. Any recommended suppliers or advice?

I bought mine from Dave at http://pro-touringf-body.com/chassis_components.html click on the link. Dave is great to work with and designs most of his parts. Mine fit great. Drilling the holes is the hardest part.

I installed the Hotchkis set & they fit great. You have to weld the rear connector to the frame.

X2 on the Hotchkis.
I have there xbrace on my 69 vert also.
I don't know the best 100% bolt-on.

I thought the Hotchkis was just a bolt in? You had to weld the rear?

Yes the instructions say to weld the rears & you can bolt the front if you like but they recommend welding the fronts as well.

The bolt-on ones require you to drill through the frame don't they? So, it's not like you aren't changing the metal down there...

Thanks guys. I haven't heard any negative comments about bolt on so I think that is the way I will go.

The bolt-on worked great for my old 68 I had. I wanted something that I could remove easily if I wanted to. However, I do think that the welded versions add more integrity to the frame, but that is my opinion.

Glad this subject was brung up. I have been looking at connectors. Wanted bolt-ins but if you have to weld in the rear then I guess I'll just buy the full weld ins.

There are bolt-ins that don't require any welding. What they do require are holes in the frame rails to bolt through. Having just had mine replaced(rear frame rails), I've had to think long and hard on whether to have holes drilled in brand new metal.

The version I used mounted at the front of the rear leaf spring and bolted to the front sub-frame. These could have been welded to the sub-frame instead of bolting them in.
It was extremely painful drilling holes in my sub-frame after repairing all of the body rot.

For those (like me) that are interested in a nice set of truely bolt-on subframe connectors, I have been eyeballing these:

Heidts RC-102

I have found while considering a set of subframe connectors that it is wise to go to the manufacturers web site to check out the installation instructions. That's where you really find out if the pair are bolt-on or not.

I put a set of bolt-on Heidt's on my vert last year. Not sure if I am remembering correctly, but I think there are different part numbers for coupe vs. vert. Very happy with mine.

I am also following this thread for my next mod. Bolt on is how I would like to go but. Then I would like to put a real tire on it.

I am going to have to do this also. Now the the bird has a few miles on it I have been getting into the throttle a little harder and feel the frame connectors are a must to minimize body twist.

It is amazing how much difference the frame connectors make, even if you just bolt them in. I highly recommend them. I installed some on my 68 428 4-speed and was thrilled with the results.

How does the difference vary between coupe and convert?

If I am correct, the convertible differs due to the extra reinforcement body pan that the coupe does not have.

You are correct. Frame connectors that hug the belly must have a notch to accommodate the convertible belly brace. The tubular connectors that dip down do not require this.

I'm not familiar with the benefits of subframe connectors - what improves when you add them?

I asked the wrong question or at best it was poorly phrased.

What I meant to ask was given that a couple has the roof which provides structural rigidity is there as much of a benefit with putting them on a coupe as with a convertible?

I definitely recommend the connectors for either application if you have a high performance set-up. The uni-body is very weak compared to its full frame counterparts. Honestly, when I would jack up the car before I added the connectors the doors would not close properly while still supported by the jack. Once I added the connectors the doors would close properly when supported by the same jack.

Be careful, too much torque without the additional support can cause seams to crack and the body to twist.

Hmmm...will I have enough torque?

Your build should produce a good amount of torque. Even with that being said, do you plan to hot rod the car at all? If so, I would suggest using the frame ties. I do not plan to use connectors on my car but I am not designing it to be a hot rod, just 300hp, not sure how much of that will make it to the rear wheels.

I am guessing your engine will produce 425-500hp, with the trans and rear set-up, plenty of torque should be there if you choose to utilize it. The Trans Am Nationals will will probably count them against you, they did for me, but the connectors are for integrity and not factory appearance.

The connectors can be the key to making sure your car holds up long after the restoration.

Would they not also provide more stability in a hard brake?

I would guess they could help with reducing the shifting of the body. What it really boils down to is comparing the strength of a full-framed car to that of a uni-body. From body integrity to a car accident, the full-framed tends to win almost every time.

I just noticed this thread. I installed a set of bolt on from JEGS. They were $99. All I can say is that was by far the best $99 I ever spent for two reasons.

One, the car never rode and or handled any better than the day I installed them. Made a HUGE difference in the way the car drove. Much stiffer and a more solid feel.

Second, when our car was rear ended at 45mph (we were sitting still), the FL State accident investigator who showed up on the scene took one look under our Bird and immediately asked if I had installed the frame connectors.

I told him I had done so only a few months before and he went on to tell me that I may have very well saved someone's life by doing so. You would not believe how well they held up under that hard hit from behind.

By installing the frame connectors if forced the trunk floor pan to take all the impact/damage. The investigator told me that was the best $99 I could have spent and I agree.

The five ruptured discs in my lower back however may not agree but hey, we all survived and that's all that matters!

It's good hear the stories of how well they work, now the question is:

*What brand is the best bang for the buck.

*What tucks up under the car the best

*Weld in or bolt in?

If I use the weld in connectors from Hotchkis is it recomended to use solid body bushing?

The price looks to very from $99 Summit specials to $379 for the Hotchkis or $569 for the chassi max system.

http://www.summitracing.com/search/Year/...rame+connectors

I'm leaning tword the Hotchkis because they seem to have a good rep and it looks like they would tuck up under the car the best.

Has anyone here used them?


I answered a few of my one questions from the pro-touring site.

The reason for solid bushings is to avoid cracking at the body where the sub bolts to.

The connectors are solidy mounted to the rear body then welded solid to the subframe. If the subframe where allowed to move and flex as it would with pliable bushings it would cause the body to crack at the floor around the nut cage. Bad news.

BMRTech
We do consider the Delrin to be a solid bushing. We have had very good results with the Delrin body mounts. They do everything an aluminum mount does and you never have to worry about corrosion. You can torque them to spec just like a solid bushing or a sleeved rubber bushing. Delrin is practically as hard as aluminum but self lubricating so they never creak like some solid bushings tend to do over time if you don't re-tighten them. I don't mean to sound like I am bashing aluminum bushings (I ran them for years in my 69 and 70 Camaros), it's just that the delrin bushings work so well I can't believe we were the first to think about building them!

BTW, I bought the Hotchkis SFC's... they are supposed to be the tightest fitting to the floor...
Pro-touring F-Body's subframe connectors also sit right up tight to the floor pan and require no body mods...can be welded or bolted in. They recommend solid body mounts.
While solid body mounts are not too bad rememebr to keep your radiator support busshings rubber to absorb any shock. I've seen some radiators vibrated to pieces, over time, when solid bushings were used on the radiator support.

I also came across Competition Engineerings non-wielding sfc's. any input on these? are they any good?
I have seen them, removed them, Hotchkis are nicer
Not very good at all.

According to the install instructions for the Hotchkis SFC for a Convertible the car is suppose to be setting on all 4 wheels and drive height. You then install the SFC while setting on all 4 wheels.
according to Hotchkis's website:
1 – Before performing the subframe connector installation, the vehicle must be completely assembled with all body and component parts installed (e.g. fenders, hood, quarterpanels, trunk, full interior, engine, glass, etc.). Basically, the subframe connectors should be one of the last components installed on your vehicle. Reason being is you want the vehicle settled with all of it’s own final weight. The car’s body is always in constant tension, with forces pushing or pulling within the chassis & body. You want to make sure these forces don’tchange after you install the subframe connectors.

Pics found here of the Hotchkis
http://www.pro-touring.com/showthread.ph...rame+connectors

What I see in the pics is if you need to change a break or fuel line you will be cutting the connectors out.

Based on my personal experience, the bolt on ones did exactly what they were supposed to do and then some. So for a mere $99 I would highly recommend them vs. not installing any. And if you want to spend a lot more on them, have at it. I'm confident that anyone who does install even the $99 bolt in, will be more than happy that they did so...

I have the Hotchkis on my vert & I'm happy with them.

Do you have any pics?

I want to see how the connectors go over the fuel lines and where it welds to.

Did yo put in solid bushing?

I will gets some pics the next time I have my car in the air. I used the bushing that Hotchkis had in the kit. It's the harder rubber/plastic type.

If you go to the Hotchkis website you can download the installation instructions. It shows some detailed photos.

Funny I just printed them out.

BTW, for those that have installed a set:

How on earth do you suspend the car up in the air (at home) such that you can support it (fully loaded) yet allow for the rear axle to hang so that you can unbolt the leaf springs at the front pocket.

Then I guess you have to put the car back on it's wheels after you have the connectors in place at the rear to bolt or weld them to the front subframe with the car resting correctly on it's suspension

Opps. Double posting. Despite pushing submit only once!

I had the muffler shop tack mine in place & then had a friend weld them the rest of the way by covering the fuel line as the instructions.

I just read through the instruction again and I can see there is a conflict. At first I thought you would install the connectors with all 4 wheels on the ground and only tac the inboard side of the connectors in the back and do what you want in the front. Then it shouldn't matter how you jack the car up to lower the rear to weld up the outboard side of the connector. But you need to drop the rear suspension to grind down to the bare metal. So unless you do it twice I don't know.


For my self I'm still wondering if I should bolt or weld or both for the front. A rosette weld would be almost impossible to remove without ruining the SF connectors. I was thinking I might bolt them in and weld the ends to the frame. They would be easy to grind off if needed.

After reading all this, I believe my car pretty much requires these. I've posted a picture here, I am guessing there aren't any already on the car, correct?