78 convertible conversion project

[milo30]

I got carried away in buying new interior parts for my 78 and got a wild hair to research convertible conversions. I am ordering most of the parts that I need tomorrow. Still need to find either a frame for the top and new top or a hard top. Saw one frame on ebay but not sure how good the condition is.

I'll be posting before, during and after pics and try to detail out what all it entailed. Anyone here done it before and can give any tips or tips on where to find the frame at a decent price?


Let's see, new engine, transmission, interior, cut off the top and new paint. I think I have my Summer taken care of. This car should last the rest of my life!

 

[Dirtfarmer]

Very interesting. Looking forward to the pics.

Good Luck.

 

[6880 Mike]

My advice is to purchase the '75 assembly instruction manual and take a look at the convertible factory installation. Going from a coupe to a convertible is a bit more involved than sawing off the halo panel. AIM will show the parts needed and their original part numbers.

Original top irons are getting pricey. You may want to consider one of the reproduction top kits.

Good luck.

 

[KANE]

I got carried away in buying new interior parts for my 78 and got a wild hair to research convertible conversions. I am ordering most of the parts that I need tomorrow. Still need to find either a frame for the top and new top or a hard top. Saw one frame on ebay but not sure how good the condition is.

I'll be posting before, during and after pics and try to detail out what all it entailed. Anyone here done it before and can give any tips or tips on where to find the frame at a decent price?


Let's see, new engine, transmission, interior, cut off the top and new paint. I think I have my Summer taken care of. This car should last the rest of my life!

Hopefully, Vick (vmrod) will chime in. He has a convertible '77.

 

[jrzvette]

Some stiffening of the frame will be necessary to add rigidity. On the coupes the halo is an integral part of the structure. I'm sure the convertibles had some additional bracing in the frame to compensate.

Or you could figure out the cost of conversion add that to the proceeds form your car and buy a 75 vert.

 

[milo30]

Some stiffening of the frame will be necessary to add rigidity. On the coupes the halo is an integral part of the structure. I'm sure the convertibles had some additional bracing in the frame to compensate.

Or you could figure out the cost of conversion add that to the proceeds form your car and buy a 75 vert.

I will have to do some checking on the earlier convertibles. I am sure that GM used one frame for both coupes and convertibles and it is my understanding that in the later C3s the frame has already been strengthened over the older models.

I understand what some are saying about take the money and buy a convertible. Unfortunately that is not an option. I already own my car and would not get anywhere near what I paid for it back right now. It's not like I am tearing apart a collectible year model plus I want the satisfaction of building it myself so unless I find a major hurdle this project is a go.

For what I got the parts for this will be a pretty inexpensive mod.

 

[3dale1]

I will have to do some checking on the earlier convertibles. I am sure that GM used one frame for both coupes and convertibles and it is my understanding that in the later C3s the frame has already been strengthened over the older models.
quote]

The chrome convertibles DID have bracing added behind the right and left dash panels. As for other areas, I don't know.

I'm also guessing that the area beneath the rear deck, behind the storage boxes and ahead of the tire carrier, had more strength in the convertible bodies vs the coupes just based on the design/shape of the fiberglass, birdcage notwithstanding.

 

[milo30]

Does anyone know what changes they did to the frames for the later year models to strengthen it? There are a couple of people in here that have done this before. Anyone know them, so maybe they can be asked?

I'll start digging around more on frames and see what I can find. If it needs it then I'll put that on my list too. LOL It's getting longer


I ran searches every way that I could think of on the internet tonight until I can't see the screen any more. I found frame specs for 69-72 and 78-82. Funny they leave out the years between. I can see the differences and specs of the 2 frames but nowhere does it specify anything different for a convertible frame. Everything that I can find shows that it is the same exact frame for any corvette of that year model.

 

[6880 Mike]

...Does anyone know what changes they did to the frames for the later year models to strengthen it?...Everything that I can find shows that it is the same exact frame for any corvette of that year model.

There is no "convertible" frame; same frame for coupes or convertibles. Convertibles have under dash bracing which coupes do not have. 68-75 AIMs show the bracing, the attaching points, and the original part numbers for what you're looking for. There are some minor differences in the bracing for AC and non-AC convertibles.

 

[milo30]

There is no "convertible" frame; same frame for coupes or convertibles. Convertibles have under dash bracing which coupes do not have. 68-75 AIMs show the bracing, the attaching points, and the original part numbers for what you're looking for. There are some minor differences in the bracing for AC and non-AC convertibles.

Thanks, this was the info that I needed. I ordered the AIMS tonight. Wish all my parts were here already.

 

[bossvette]

my 68 vert had only the hard top when I bought it; I pieced together a top from Ebay and various sources here is the old thread

http://www.corvetteactioncenter.com/forums/showthread.php?t=94144

 

[Scott Winebarger]

I'll be watching this one, good luck !

 

[milo30]

my 68 vert had only the hard top when I bought it; I pieced together a top from Ebay and various sources here is the old thread

http://www.corvetteactioncenter.com/forums/showthread.php?t=94144

Thanks that will be helpful. thank you could get me some pics of yours behind the door where I am going to have to cut so I can have something to go by? Any pics will help me.

Thanks for the link

 

[sstearns2]

....

Have you seen this one?

http://www.uscorvettes.com/cardetail.php?listcar=120

Scott

 

[milo30]

I was thinking about that rear section with the spoiler but I don't think I like it on a vert. The top didn't seem to fit right unless they didn't fully open it for the pics.

I still think C3 convertibles are the best looking cars I have ever seen.

 

[6880 Mike]

...The top didn't seem to fit right...

I agree. Worst I've seen. Looks like owner fabricated mounts.

Why does this car ride high in the rear? Makes me wonder whether losing the weight of that glass hatch raises the rear quarters.

 

[milo30]

Yeah the rear does look a little too high. Mine is way too low right now. I was looking into an air suspension anyway where the ride height could be adjusted so this shouldn't be a problem.

That top though just looks bad. It almost looks like they just lifted it and then not seat it down for the pic.


My interior parts have started arriving today so I am getting excited but still a little scared at the thought of cutting the finerglass. Knowing that once I start this there's no turning back. LOL

 

[bossvette]

Thanks that will be helpful. thank you could get me some pics of yours behind the door where I am going to have to cut so I can have something to go by? Any pics will help me.

Thanks for the link

pic behind the door

mine is different then the 82 CE "mimic" I do not know what year my top frame is; I bought it off Ebay as a 68-75, but I suspect it is an early frame and may even be from a 68; there were minor changes in the frame things like bigger threads in the pin for the decklid and where the side wires attach


also that 82 CE mimic is running a carb motor the 82's had crossfire injection

 

[milo30]

Great, thank you. that was exactly the picture I was wanting to see.

Fun day here. Delivery trucks keep rolling in.

 

[vmrod]

Hey there. Bossman pointed the way here for me, as I don't check in as much as I should.

I have a '77 vert and could post pics of things for you. Mind you, I have not done the conversion myself, but bought it this way. I have however changed out the major systems in the car.

If you need a new engine, tranny, and conversion kit, you may wanna just look into purchasing a car that already has all of this stuff. I heard a conversion could cost $5k or more! Add the price for the other things and that is the price of a complete car!

(added)

Also, if you wanna change your ride height higher, just tighten up the nuts that pass through the end of your rear leaf spring. That will ift the car up. Loosening the nuts will lower the height. Sounds backwards, but that is how it is. Also, make darn sure those nuts never come loose (at least while driving). Happened to me once. Not fun.