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stmotorsports 10-25-2011 03:57 PM

57 Chevy- convertible from 2dr post?
Yeah, I know. This again. I know this question/issue has been raised several times in the past, but it never seems like there is any kind of definitive answer as to how feasible it actually is or isn't. So I'll try to be as specific as possible with my goals and reasons for asking this in the first place.

Here's the thing- I already have several projects of my own, but have been kicking around the idea of building a 57 convertible cruiser for my parents as a retirement present. The primary constraint being I'm definitely not looking to make this a 50k+ build, and definitely not a concourse car, just a decent looking sunday cruiser. I've been looking for real vert for close to 3 yrs now with no real worthwhile candidates (either ridiculously overpriced or not much left beyond a pile of dust, and even those are usually overpriced). At this point I'd rather just get moving on something than waiting til the cows come home to find a real vert worth building. I have pretty extensive experience with fab/welding/body/collision/paint/etc, I've always done virtually all my own work, and have even done a few convertible conversions in the past, so unless the bodies are just completely different proportionally, I don't see what is so undoable about this.

And my reason for saying 2dr post is that these things are a dime a dozen, and i would never ruin an otherwise good hardtop, I would just keep it a hardtop. Same reason why I won't cut my 54 hardtop ;)

So my main q is for the real hardcore fabricators here- just how far off is a real vert body from a post once you cut the roof and posts? Meaning- aside from chassis differences and body reinforcing/braces/etc, if you put a real vert body and a cut post body next to each other, are they basically identical? Meaning in terms of proportions- trunk length/etc? Like could you cut a 2dr post and fit a convertible top right on? What is the main hold up that make so many people say that it can't be done/too much of a hassle/not worth doing?

poncho62 10-25-2011 04:04 PM

I'm not an expert, but I do know that the hardtop and convertible had a shorter passenger area, thus a wider panel in front of the trunk to the rear window

That said....2 dr sedan 55-57s are very popular......shame to hack one up in my opinion

Dave57210 10-25-2011 04:09 PM

57 'vert
Header, cowl & windshield are also different between a post & a ragtop

Check windshield compatibility - I don't know for sure but maybe the windshield is unique to the ragtop

Yes, so far as I know fenders, trunk, quarters (at least the outside skins on the quarters) etc are the same for both, and yes chassis is VERY different, as are front & rear cowl bracing.

Some guys are getting stupid $$$$ for just a firewall, cowl & windshield header from a rusted pile of junk ragtop, so that a sedan can made into a ragtop and have the right stuff, including a correct firewall code tag.

oldschool hero 10-25-2011 04:15 PM

Google convertable conversions. I recall a co. in Texas sells a kit for the tri 5s .It ain't cheap as far as I recall. They sold kits to convert 4 doors into converts, All you need is the frame and cowel.

stmotorsports 10-25-2011 04:17 PM

I kind of assumed the boot area would need to be larger in the verts because it needs to accommodate the top frame and mechanicals where there is normally just the little rear shelf.

Does anyone know what's different about the windshield/cowl/etc? I don't even care about the vin, I'm not trying to fool anyone. Like I said, just looking to build a decent cruiser.

I did some searching for the conversion kits, but was having trouble finding anything. Plus anything I came across mentioned the kits out there were only for 2/4dr hardtops so I lost interest. Plus when you do all your own fabricating, I don't really need a kit. Especially when the kits are $7-8k for a some sheetmetal :rolleyes:

I love posts also, but they're quite a bit more common so I doubt the world will miss just one. Especially since I know of a couple with caved in roofs that have just been sitting like that for years and will probably never be otherwise fixed. I figure cutting one into a vert is still better than a post being left to die.

OneMoreTime 10-25-2011 04:24 PM

Main structural consideration in making a convert out of a sedan is the top does provide for structure of the body..I cut the top off of a car once for a field beater and it sagged in the middle so badly after a while that the doors would not open and we had to jack it up in the middle to close them. Did not matter all that much at the time as we were kids having fun..


35terraplane 10-25-2011 04:26 PM

Chip Foose made one out of a 4dr hardtop on his show, they used 2dr quarter panels. I don't think they had a working top on it, could have been because of the time for TV.


mafiacustomz 10-25-2011 07:49 PM

why not try a hard top convertible as in like the new caddys or other high end cars i think that would be easier thin a rad top convertible by far and would look realy sweet

Chevymon 10-25-2011 08:07 PM

4 Attachment(s)
This is a 4 dr sedan conversion, which is the same as a two door in every respect except the doors, the roof is even the same.

In one picture you can see where they welded the convertible windshield frame on. The doors are different from hardtop at the vent window top, but can be modified. The floor is the same except the rear floor pans, and the trunk floor is the same except for a couple of extra body mounts. The complete inner side wall from door to tail light is different, and there are extra supports and braces around the top henge area. The trunk henge area is a little different, but all of these panels are available to buy new.
The difference in the frame is an x member that is welded in and two flat pieces welded on the bottom of the frame rails, all of which is also available new. All the frames are the same except for body mount locations and the x member on the convertible. You can get everything new, or even a new assembled body.

If you order a catalog from CARS it will list everything you need to make the conversion. But after you do all the metal work, then there is a lot of stainless steel trim that is specific to the convertible and very expensive.

66GMC 10-25-2011 08:28 PM

I'll apologize in advance for straying off-topic here.

The title "convertible from 2-door" brought back an old memory.

It was a late 70's Chrysler Cordoba (about 5 years old at the time, IIRC) that came into the bodyshop on the hook.

Somebody had chopped the roof off in a "DIY convertible" attempt.
The rear bumper was about 6 ft. off the ground, while the front fenders were paralell to the ground. :D
The doors wouldn't close (obviously) and were tied "almost shut" with a peice of yellow nylon rope.

One could only imagine the owner's reaction ... :eek:

TucsonJay 10-25-2011 09:09 PM

I know that the sedan had a taller windshield than a hardtop... and therefore taller than a convertible too.

Chevymon 10-26-2011 09:59 AM

The windshield frame is totally different on a sedan, and the windshield glass is different also.

stmotorsports 10-26-2011 07:10 PM

hmm... upon looking at about 50 million pics it appears that the qtr panels are different between vert/ht's and sedans... the spot where the qtr hips up behind the door seems to be more pronounced on the vert/ht's and less so on the sedans. Several vendors show replacement qtrs being different or available for one but not the other. Hmm... looks like I might have to find a ht after all or a sedan that needs qtrs anyways...

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