Fox Body chassis from the Roadster Shop

Yes, you read that right - a Fox Body CHASSIS. 

Obviously, Fox bodies are unibodys - sheet metal stamped and welded together into a body, then all the driveline and suspension bits are bolted to it. Not the strongest way to build a car, but it is cheap. Subframe connectors, roll cages, all kinds of band aid fixes have been tried over the years - now, you can get a complete, bolt-in, rolling chassis that is designed to accommodate nearly any engine/trans combo you want - Coyote, Godzilla, SBF, even LS - 9 inch rear axle, etc.

   SEMA Show 2024: Roadster Shop’s New Fox Mustang Chassis, Exclusive First Look

I've had a notchback 5.0 LX project at the back of mind for years.....all of a sudden things got a lot more interesting. 

In reply to earlybroncoguy1 :

What surprised me is the price. 16K for that level of upgrade is pretty reasonable.

We had their RS63 Corvette in our shop a couple years ago. The build quality was incredible.

If that car is anything to go by, I'd expect the quality to be excellent

In reply to earlybroncoguy1 :

A unibody is technically a type of chassis It might be more descriptive to call it a foxbody add-on ladder frame.

Also unibodies are generally superior to ladder frames in all aspects of performance, especially stiffness, they're just far harder to fix and modify and they make the vehicle far less modular. I think manufacturers prefer them for packaging advantages more than any price difference. Most pickups still use ladder frames though.

Dang. That is really cool, and I agree, the price seems pretty reasonable for everything you get. If I had the spare cash and skills, I'd be looking for a bubble-back Capri to drop on to that.

So, you have the weight of the unibody and the chassis? And you raise the body up by putting it on a chassis? Seems odd, but it sounds like they thought of that and came up with a pretty good solution. I applaud anyone keeping the beautiful notchback Fox body on the streets for another few decades. 

pinchvalve (Forum Supporter) said:

So, you have the weight of the unibody and the chassis? And you raise the body up by putting it on a chassis? Seems odd, but it sounds like they thought of that and came up with a pretty good solution. I applaud anyone keeping the beautiful notchback Fox body on the streets for another few decades. 

have you ever read Matt's article on that car?  he ended up spending 2 or 3times what he budgeted to build that car and I think when he sold it there was still some sorting that needed to be done.  
https://www.speedhunters.com/2018/03/experience-required-matt-farahs-88-fox-body/

ClearWaterMS said:

have you ever read Matt's article on that car?  he ended up spending 2 or 3times what he budgeted to build that car and I think when he sold it there was still some sorting that needed to be done.  
https://www.speedhunters.com/2018/03/experience-required-matt-farahs-88-fox-body/

Yeah, but he'd be the first to admit he didn't approach it in the most cost-effective way. And didn't he have a Porsche specialist shop (BBI Autosport) do most of the work? The result was an amazing car, but it also kind of got away from him and didn't end up being what he wanted.

Tom1200 said:

In reply to earlybroncoguy1 :

What surprised me is the price. 16K for that level of upgrade is pretty reasonable.

That seems incredibly cheap for the effort gone into design.

That's pretty cool, and makes me wonder what other older "iconic" unibody cars could benefit from a similar solution.

In reply to pinchvalve (Forum Supporter) :

I am sure one could fab up some weld on plates to join the ladder frame to the unibody.

Perhaps one day I will do his to my Foxbody but for now I'm enjoying my "back in the day" set up.

BlueInGreen - Jon said:

That's pretty cool, and makes me wonder what other older "iconic" unibody cars could benefit from a similar solution.

all of them...  The fox body however is one of the few that is popular enough to sell enough of those 

I wonder what this new chassis weighs compared to a Fox with all the usual upgrades like subframe connectors, rear axle, etc. If the total package is within a couple hundred pounds difference, the suspension upgrades are probably well worth the weight, especially that slick double-wishbone front end. Really cool product.

They claim zero weight gain over the removed stock bits, as well as both improved ground clearance and lower ride height.

 If it delivers all that, it's a beautiful execution of integration and improvement.

 The bolt in aspect is really cool, but I can't help wondering whether they've worked on any points to tie in other reinforcements. A ladder chassis is just silly for stiffness even if a tubular one can clearly add to an existing chassis and do better than subframe connectors. But going 3D would obviously break the bolt on part.

I was pretty stunned to see what was included at that price. Fox shocks! Even lower end ones; I was expecting that price to be the bare chassis, no control arms, no nothing.

Tom1200 said:

In reply to earlybroncoguy1 :

What surprised me is the price. 16K for that level of upgrade is pretty reasonable.

Yeah, I expected it to fetch more, too.

So, what driveline is everyone going with? 

It's a pretty intriguing implementation of a generally dismissed concept, that I think could be fun to apply at a Challenge level. Could even help for converting FWD cars to RWD too... Just sayin'.

Beyond being interested to see what they mean for their 'optimized' suspension geometries, I'm also curious about the 'improved ground clearance" claim with box tubing below the floor pan. I'm guessing that's simply relative to the the lowest point, but possibly still might have worse clearance in other critical areas, like under the rockers.

In reply to Tom1200 :

16K is a slightly misleading.

That gets you the bare chassis, bare 9" with no center section, no brakes, no fuel tank (not sure if the factory one can be reused), no engine mounts, no trans mounts, base model coilovers (still nice, IMHO)

Outfitted more complete, I think the one I spec'd out was like 28K

Which, is awesome that it's available for those that are willing to pay

maschinenbau said:

I wonder what this new chassis weighs compared to a Fox with all the usual upgrades like subframe connectors, rear axle, etc. If the total package is within a couple hundred pounds difference, the suspension upgrades are probably well worth the weight, especially that slick double-wishbone front end. Really cool product.

I'm questioning this too.  While not light, Fox chassis front K-Members, even fully dressed, are nowhere near the weight of a full fabricated frame. 

And having cut apart and fabricated alot on a Fox Body, the factory torque boxes aren't heavy.

The 9" is substantially heavier than an 8.8 too.

I'm just struggling to see the weight being equal.

What needs to be changed to fit other Fox body platforms?

Building a TBird could be...  Well, you know.

I love this Fox Body buck(?) that they made for display.

I do know that the stock crossmember is near 50lbs and the control arms are 13lbs each. So I'm sure there is a 40-50lbs weight savings in just the front end. No idea what the stock fuel tank weighs versus the stainless one this would require.

As for the cost not including certain things it did mention using existing 5 lug set ups so one could transfer over your existing brakes.

Regardless of what all is need I think this is really cool.

it's nice to know for once I picked a chassis with unlimited potential.

ClearWaterMS said:

BlueInGreen - Jon said:

That's pretty cool, and makes me wonder what other older "iconic" unibody cars could benefit from a similar solution.

all of them...  The fox body however is one of the few that is popular enough to sell enough of those 

Roadster shop also sells chassis for earlier generation Mustangs, Camaros and Firebirds, early Novas, as well as a number of non-unibody cars.  I believe they'll custom build a chassis too if you have the $$$, the last time I looked at their website they were building a 1961 Pontiac Catalina, a 1950s Buick and a 1949 Mercury.

Noddaz said:

What needs to be changed to fit other Fox body platforms?

Building a TBird could be...  Well, you know.

Wheelbase for one.

Also, there is a vertical height difference between the front kmember mounts on a Tbird vs Mustang.

Looking at how tightly this seems packaged to the underbody, I'd plan on interference at every interface point, and several close proximity locations. Unibody channels, seat pans, upper torque box locations, fuel tank mounts, etc

Fox body cool, can you put it under a Fairmont?

HotNotch said:

maschinenbau said:

I wonder what this new chassis weighs compared to a Fox with all the usual upgrades like subframe connectors, rear axle, etc. If the total package is within a couple hundred pounds difference, the suspension upgrades are probably well worth the weight, especially that slick double-wishbone front end. Really cool product.

I'm questioning this too.  While not light, Fox chassis front K-Members, even fully dressed, are nowhere near the weight of a full fabricated frame. 

And having cut apart and fabricated alot on a Fox Body, the factory torque boxes aren't heavy.

The 9" is substantially heavier than an 8.8 too.

I'm just struggling to see the weight being equal.

It looks like much of the frame is more like a channel/sleeve that slips over the existing body rails.  I assume that the frame itself is kind of noodly and is partially dependent on the tub that bolts to it for its strength.

The 8.8 is fairly light (and I would argue is just as strong as a 9") but you can make a 9" light fairly easily.  My 9" rear weighs about 190lb with brakes, and it doesn't even have a spool or lightweighted gears, and it has a thickwall truck housing and 31" spline axles.  59" flange to flange.

Mind you, most Foxes didn't come with 8.8s, all V8 cars up until some point in the mid-late 80s had the 7.5 as did four cylinder and V6 cars.  The real light Foxes were the early ones.