C4 Dual Roof Option

[Carlo Miceli]

Purchased my '88 used in 1989 with the bronze glass roof installed. Had no idea at the time that the vehicle originally came with dual roofs. Previous owner made an extra few bucks at my expense.
Now looking to find a replacement factory fiberglass roof to keep things original. How do I distinuish a factory piece from an aftermarket (such as Astro). Does it matter for judging purposes?
I know that the mounting is unique for late '86-'88. Is there anything else I should be looking out for? Any suggestions for locating a show condition piece?
Any and all insight on the dual roof option is appreciated.

[Joe L.]

Re: C4 Dual Roof Option

Carlo-----

Actually, I don't know if anyone makes a reproduction of the fiberglass C4 top. I thought that all of the reproductions were of the clear tops. I could be wrong about this, but I just don't think that I've ever seen or heard of a fiberglass replacement top.

If any are made, though, I expect that they are easily discerned from original GM.

I think that your best bet would be to contact a used parts dealer that specializes in C4's. Someone like Steve Arcoleo in New York (718-331-0456). They part out a lot of C4's. I'm sure that he has these tops in stock and he will know exactly which one is the one you need. In fact, I expect that he has enough of these in stock that he might even have one in the color you need.

[Joe L.]

Addendum

Carlo-----

I forgot to deal with a few parts of your question. First, as far as how to distinguish between C4 tops, the easiest way is to look at the brackets on either side of the front corners where it attaches to the windshield frame area. For 1984-E86, the attachment is accomplished with a "tapered pin" and a bolt. Fpr L-86-88, there's a bracket on each side which are more-or-less "rectangular" with an extension for the area where the attachment occurs. For 89-96, the bracket is more-or-less "triangular". I've attached sketches below of the brackets. You should be able to see an example of the bracket on the acrylic top you have. You want a fiberglass top with exactly the same style brackets. If you find one like that, then you've found the right one.

The dual roof option simply supplied BOTH the standard fiberglass top PLUS a clear acrylic panel in choice of blue or bronze tint. With this option, the extra top was installed in the holding fixtures in the luggage compartment. I've forgotten which top was actually on the car as-delivered.

If one ordered just the acrylic top option, then one got the acrylic top in choice of tints and NO fiberglass top.

If one ordered no top option, then one got only the fiberglass top with no clear, acrylic top, at all.

[Carlo Miceli]

Re: Addendum

Thanks for taking the time Joe.
If anyone is interested, there is an outfit called Thompson Astro Tops that reproduce both the acrylic and the fiberglass units. See link below.
I just wonder how to tell them apart although I will call the supplier in New York mentioned previously.

http://www.astrotops.com

[Joe L.]

Re: Addendum

Carlo-----

From their web-sire it looks like the fiberglass panels for C4's are a very new item; they don't even have any information about them on their web-site. So, I doubt that there are many of them "out there" yet. However, my guess is that there will be significant differences from the original tops, either in configuration and/or component quality.