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-   -   Aftermarket chassis or not? (https://www.hotrodders.com/forum/aftermarket-chassis-not-523059.html)

curtis73 09-26-2019 02:26 PM

Aftermarket chassis or not?
 
Started tearing into my 67 LeMans convertible project. Headed in a sorta pro-touring vein; Body will remain mostly stock, custom interior, 500-hp LS6/LQ9, T56, insert axle here (maybe a 9" if the one I have isn't too narrow)

The vehicle itself has 276k on it, and the frame has had a rust repair done. It's mostly a wet noodle, so something needs to be done. At bare minimum I'm thinking brakes and a refreshed/upgraded suspension, but there is also the option of big-dollar aftermarket stuff.

I don't think I need to go full-on Schwartz chassis since I've never needed 1G cornering, and since this is also going to be something I want to actually drive whenever I want, I don't want unobtainium/expensive parts. For instance, I would rather have some LS1-era F-body discs up front and off-the-shelf brake parts out back on an 8.8 or 9" so I'm not ordering Brembo or Wilwood every time I need to do maintenance. This will be a driver, not a HPDE or trailer queen. (Ok, maybe some HPDE stuff) I want to be able to drive cross country with it, not hide it in a garage.

Do I get an aftermarket frame, or try to stiffen up a stock frame?

johnsongrass1 09-26-2019 02:47 PM

AFCO makes a nice aftermarket version of those that you jig up and weld together so that might be something to look at for repairing yours.

curtis73 09-26-2019 03:01 PM

I had seen that, but they only list 68-72. The 64-67 were specific, especially when it came to convertibles. Any insight?

johnsongrass1 09-26-2019 03:18 PM

Not really. I didn't realize they were different.

techinspector1 09-26-2019 03:39 PM

Try these fellows, they've been around for a long time.......
Chassis & Custom Suspension Manufacturers*| Auto Weld Chassis

39 master 09-26-2019 04:19 PM

Two things: First I like your statement about using "off-the-shelf" parts. While on a road trip replacement parts are just around the corner and not have to be flown in. Second, can't build a house on shifting sands. Rather you get an after market frame or repair, upgrade, fix and paint you will never be happy unless you have a sound "foundation".

curtis73 09-26-2019 04:35 PM

Techinspector, thanks for that resource.

39 master, I agree. I can engineer a decent suspension geometry and I'm an above average welder. I'm just curious if I can get any significant additional stiffness from modifying a stock frame versus the weight savings and rigidity of an aftermarket frame.

I have already spoken with Schwartz and they are very eager to help out with parts choices if I decide to buy just a bare frame and put my own components on, but even just the bare frame is $8000-10,000. I'm hoping for a middle of the road solution. I don't need the 1G that Schwartz frame can offer, nor do I want a $10k price tag. I'm hoping for a $5k price tag and a good, solid improvement over the wet noodle I have now.

curtis73 09-26-2019 04:54 PM

Just got off the phone with AutoWeld. Fantastic resource, but he said that since they've never done that A-body, I would have to absorb some of the cost of making the jig and he quoted $15-18k since it would be a complete custom job start to finish. We both agreed that they were more toward the Pro Street, Mustang2 end of the spectrum and I'm more on the Pro Touring, C4 end of the spectrum.

techinspector1 09-26-2019 06:36 PM

Well then, I would just build a jig and make the damned thing myself. It's just tubing, welding wire/gas and labor. And you have a pattern to start your jig with........

curtis73 09-27-2019 10:12 AM

Welll… I have the welder and I can build a jig with some wood, but I can't duplicate mandrel bends and the R&D that goes into an aftermarket frame. I also have a one-car garage full of motorcycle and tractor. Suffice it to say, it's worth $5k or so to upgrade instead of starting from scratch.

idrivejunk 09-27-2019 11:40 AM

I passed the thread title over because I do body work at a shop that puts various aftermarket frames under various bodies. Finally read it though, and I think I may have something to add without anyone yelling advertising.

First off, be it known that few whiz-bang new frames "bolt up". Bodywork required. That being said, the fact that you have a 67 LeMans convertible made me think...

A job came through a few years back which is pretty much your exact scenario. Last time I knew, and I don't know the current owners, they were calling it the Sugar Shack GTO (a 65 convertible) and it was every bit of a quarter million dollar build if not more, but we were the shop who finished it, and it came to us with a frame which might interest you already under it. I have plenty of pics, but the idea seed may be all you need.

They took what I would call the stock torque box corners... basically just the curved kickup areas, and built onto those. Seems like an easy way to go about what you're after. You can fix and reinforce the reused sections to the moon if you like but they keep the stock dimensions in place and you are free to graft on what you wish.

Of course, this puts your car down the whole time. Unless you can find a suitable donor frame. Since you have read through the whole disclaimer part now ha ha, I will see about digging up some images. I think there was quite a bit of overkill on it but am no chassis designer. Stand by for a couple inspo pix.

idrivejunk 09-27-2019 12:25 PM

https://1.bp.blogspot.com/-XbM1MI_sS...0/IMG_1319.JPG

https://1.bp.blogspot.com/-c6tbUDs4n...0/IMG_1370.JPG

https://1.bp.blogspot.com/-YNlgOGgUE...0/IMG_7712.JPG

https://1.bp.blogspot.com/-7lstEtC6W...0/IMG_7713.JPG

https://1.bp.blogspot.com/-qnmIki_4m...0/IMG_7711.JPG

https://1.bp.blogspot.com/-fIb8993pl...0/IMG_9121.JPG

https://1.bp.blogspot.com/-QE-GWqdxc...0/IMG_1439.JPG

https://1.bp.blogspot.com/-Dke3orwGI...0/IMG_5183.JPG

CaptMike 09-27-2019 02:04 PM

4 Attachment(s)
If your frame is reparable, I can tell you from experience it will probably be less expensive and less labor to repair it and bracing. But, it'd really nice to work with an all new frame and set up everything without any mods to a frame.

AME (Art Morrison Enterprises in Fife WA) will Fab a perimeter frame or frame rails. They have quite a large selection.

I sent a CAD drawing to Brock @ Art Morrison Enterprises in Fife WA and they bent my Frame Rails for my '37 Chevy Coupe build to our Spec, was less than $1K with extra tubing sections. I chose C4 Corvette IFS and got my front cross member from Don @ Flat Out Engineering in Orange CA. The rear suspension uses the C4 Spindles and Dutchman's 9 inch IRS Center Section.

I have some experience with the Corvette C4 IFS & IRS, and I had a bunch of the components on hand. AME also bent my Roll Cage pieces. All where just about as perfect as can be had. Making the Frame Extension for the Body mounts was relatively simple.

As shown in the photos the frame rails are a work of art. We TIG welded on a frame table loaned to me by a friend.

IF your a DIY Guy and can at least tack weld, TIG Pro's can be found that will weld on location.

Michael..

39 master 09-27-2019 07:24 PM

Chassis
 
2 Attachment(s)
FWIW department I build my own frame for the '39. No blueprints were available so I plumpbobbed the outline to the ground and made a set of drawings. Got two sticks of 2" X 4" 11 gauge and went at it. Turns out the frame was very easy to build and would recommend it to anyone who can fab. The finished product will not be as nice as a mandrel bent $10K frame but for under $500 and tucked up under the car it works just fine.

curtis73 09-30-2019 04:54 PM

Quote:

Originally Posted by CaptMike (Post 4696609)
If your frame is reparable, I can tell you from experience it will probably be less expensive and less labor to repair it and bracing. But, it'd really nice to work with an all new frame and set up everything without any mods to a frame.

AME (Art Morrison Enterprises in Fife WA) will Fab a perimeter frame or frame rails. They have quite a large selection.

I sent a CAD drawing to Brock @ Art Morrison Enterprises in Fife WA and they bent my Frame Rails for my '37 Chevy Coupe build to our Spec, was less than $1K with extra tubing sections. I chose C4 Corvette IFS and got my front cross member from Don @ Flat Out Engineering in Orange CA. The rear suspension uses the C4 Spindles and Dutchman's 9 inch IRS Center Section.

I have some experience with the Corvette C4 IFS & IRS, and I had a bunch of the components on hand. AME also bent my Roll Cage pieces. All where just about as perfect as can be had. Making the Frame Extension for the Body mounts was relatively simple.

As shown in the photos the frame rails are a work of art. We TIG welded on a frame table loaned to me by a friend.

IF your a DIY Guy and can at least tack weld, TIG Pro's can be found that will weld on location.

Michael..

I have given considerable thought to what you suggest. I was thinking of basically bucking a stock frame on the floor, welding in some center ladder parts, then cutting out the heavy parts on the perimeter and welding in some 2x4 tube. I have no idea if that would be any good (not a real engineer but I play one on TV).

The real draw to something like a Schwartz frame is that it (at least claims) 100+ lbs lighter, 200% stiffer, and requires zero body mods. (unless you want to tub it to fit 345mm.) I guess it's a question of whether or not I'd rather open the wallet and capitalize on someone else's engineering, or if I want to take a $500 chance on trying it myself.


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