Making a 4 door into a 2 door, 57 or 58?

[brushwolf]

Here is my unsuspecting victim. Bought for $800 about 15 years ago to use the front clip and power seat base, 352 Interceptor and CM, PS, PB for retractable parts. Everyone I have ever told that to (particularly my youngest son) has freaked about it cuz it is <100k mile original car, good front clip, bumpers, good floors and trunk, titled with collector plates. Runs but water pump now leaking and brakes are sketchy.

It has some big hail dents on the roof and some also on the trunk lid, plus some added holes in the top from a rooftop luggage rack being bolted on it sometime in the past. It is a MN car, but was told the first owner never drove it winters and has only been yard driven since I got it.

[brushwolf]

Looking in the trunk you can see why I want to retain the original wheel tubs and as much other original metal from the 4 door as possible.. I believe the wheel tubs are identical to convertible with the exception of the lip on the top of the well being hammered over at the factory for mechanical folding top mechanism frame clearance.

Rear floor pans are different and tunnel height inside car are quite different so I will have to cut some good metal anyway for X frame clearance. Back seat from 58 convertible is pretty far gone, but I have retractable back seats too which I have heard are the same except the vertical angle. Guess I will find out.

[alvin stadel]

I do not envy you a bit. I used a 2dht body to put all the convert stuff in. It is a lot of work but very rewarding. I had friends that said I was nuts, maybe so, but in the end it turned out great. However to be honest, if I live another 74 years I would never do it again. I know you know this but use plentey of bracing, very important. I am not sure if you are reusing the cowel , dog legs and header from the convertable. I cut just below the dog legs of the convertable and transplanted them onto the 2drht body, you will need this for header strength. This is one build I will follow to the end.

[brushwolf]

Yes, it is more work than probably makes sense to most people. But, I enjoy the challenge. I could just buy an intact one if I really wanted to, but it would probably very soon just sit in the pole building with the 55 Crown and I would soon just go back out and work on some other oddball marginal logic project anyway. Doing it is frequently frustrating, but also satisfying to me. I would probably steal the "Graveyard Cars" tag, but it is already spoken for by Mark the Mopar guy.

The replacement of left and right windshield posts along with the top of windshield frame is what I did on my 57 convertible also. The cowl on mine actually came from a 57 Custom 4 door CA cop car, spot welds drilled out and then plug welded back together. So, I have dealt with the windshield before to some extent, but not the upper rear body changes cuz my 57 convertible was pretty complete back of the doors, though needing floors and lower quarters.

The 58 convertible had a tree fall on top of the windshield so that screwed up the top front header bow and top of windshield frame. I might be able to fix the front header bow if I just can't find another, but it is pretty rough so looking for another one preferably.

Same for top of the windshield frame. I do have a couple cowls with good windshield frames that are from/on 57-58 retractables that are probably the same on windshield side posts, but underneath the stainless on top of the windshield frame, the top half of 2 piece upper windshield frame structure is a different side profile to match the differing metal top fastening screw mechanisms and placement of those. But, if you looked at a photo of the front half of a retractable and a convertible with the tops down, they are pretty hard to tell apart.

Both of those (top of windshield frame and header bow) could end up being Fitzee Fabrications type piece-by-piece work if I can't get replacements. But, that gives me another idea to investigate on possibly modifying retractable windshield frames. Maybe have to take one of those apart structurally tomorrow to see what the possibilities are.

I talked to a guy in Nebraska tonight that says he has at least one, maybe 2 57-58 convertible cowls, and possibly a header bow. But not sure if we will be able to work something out since I don't really want or need another entire cowl and he rightfully views the selling of just the top and sides of a windshield frame as making the rest of it worthless.

And if he has titles/vin plates for those that would just about guarantee he will probably want more than I want to pay. I can do an awful lot of fabrication work in the time it would take to go get it as well and I can use my 57 convertible for a jig to make sure it all fits together well before final welding.

How did you do the rear part between the trunk lid and convertible top rear curtain?  Install the entire top metal and front trunk lip with the substructure off the convertible and cut out the hardtop one?  I see the substructure under that is not the same shape underneath between sedan and convertible. Convertible has a thicker profile substructure ahead of the front of trunk lid and inside the trunk, plus the shaped edge on the top side of that piece for pot metal trim at the base of the top, the drain chutes, etc.

Did you also use a set of the shorter, firmer convertible body mounts since they also differ between convertible and retractable cars compared to the rest of the lineup of fixed roof cars?

Giving you a memory test now. 

[brushwolf]

This section behind the rear window/curtain in case it was not clear what I was talking about...

[alvin stadel]

Yes, you are giving me a memory test. It has been over 20ears since I built mine. I have a lot of pictures, that I have not looked at for a long time but will look now. As I recall I cut along the top of the fin where the 1/4 trim goes. We took it from the door jamb to the top of the trunk, deck lid . There was a lead filled joint on both sides that I believe is where it was cut.  Cutting it apart was the easy part. Putting it into the hard top body was a challenge. This is one area I had extra bracing , to be sure the top frame would line up correctly with the windshield header. We had to tack weld it a few times to get it just right but then i went very well. My top moves to the right about a 1/4 inch when I lock it down, but I think they did that when new and original. Now you have me wondering about a couple of things so it is time to go dig my pictures out. One thing I remember for sure is don't get in a hurry, it will all come together if you give it a chance. Take care, Alvin

[brushwolf]

" I cut along the top of the fin where the 1/4 trim goes. We took it from the door jamb to the top of the trunk, deck lid . There was a lead filled joint on both sides that I believe is where it was cut."

Yes, that fin trim goes there on the quarter peak on a 57 so it would be the logical spot, but this being a 58 with different quarter trim placement IDK if it is optimal to do it that way for a 58. Think a former neighbor bodyman told me once that if I had to choose between a peak and a flat or low spot to make a weld joint graft, the peak is stronger and resists warpage much better but the low spot is better for making an invisible joint and you want avoid having filler on the extruding peaks.

Being a 4 door complicates it more of course. So I am tentatively thinking that I will graft in the convertible door post and as much of the front quarter as fits in one piece and doing a vertical joint with 4 door quarter where back of rear door currently resides. Then cut that section horizontally under where wide 58 side trim fits and use new lower patch panels or parts of rear doors to fix the rusty bottoms there. My rear quarter glass window mounts for tracks are all in the inner structure of that piece too so that will hopefully work out.

Did you drill out the rear seat vertical support structure and replace it with the convertible one as a separate piece, or left it welded to the inner quarter convertible structural supports too and welded it factory bracing and all as one complex but dimensionally intact piece?

" This is one area I had extra bracing , to be sure the top frame would line up correctly with the windshield header. We had to tack weld it a few times to get it just right"

Yes, I have made that mistake of welding stuff too good multiple times without completely checking fit of all subsequent pieces that attach to it, so hopefully have learned my lesson on that expediency mistake by now. Tack it very solid, no more.. Then check fit of ALL subsequently dependent structural components and trim.  Only then do the substantive welding.

"My top moves to the right about a 1/4 inch when I lock it down". 

My 57 does as well and did before I took it apart too. I think that can be adjusted out, but it does not seem to cause any problems so I left mine too. The 57 convertible I had when I was 16 did the same thing, so I think you are right that many came that way. My excuse is that "it's factory designed that way".  Might also cause fabric tension issues on a complete top to try adjusting it any time after fabric installation would be my guess.

[alvin stadel]

Yes we changed out the seat supports, I am not so sure that we would of had to, but it all went back to geter ok. I will tell you this if you can make it work with out cutting and welding leave it alone. It takes a lot of time to get it back like factory. The seat supports andis one I think would have been fine without changing.  You have got to remember my build was 20 years ago and you are making my old retired mind work overtime.