c4 chassis frame

[tony reilly]

Hi Guys,

I'm well on the way toward buying an '88 or '89 coupe and have some questions about the chassis I hope someone can elighten me on.

The "Black Book" mentions that the '87 Z52 option included the structual improvements required for the '86 and up convertibles. The "Buyers Guide" , also by Antonick, 4th ed., p 147, shows several additional structual members for the convertible. I recently inspected an '89 on a rack and didn't notice any "X" frame but I wasn't particularly looking for these members since it was the first I've been under.

My questions are:
What structual members were added to the '87 Z52 coupe?
Were these members included in the '88 Z52 coupe?
Were these members included in all '89 coupes since Z52 was dropped?

Your help is always very appreciated,
Tony Reilly

[Joe L.]

Re: c4 chassis frame

Tony------

The 86-88 C4 frame variances are a VERY complicated area. However, I'm going to try to "boil it down" to answer your specific questions. First of all, though, let me say that the "X-brace" was a convertible-only item. It was NOT used on coupes---Z-51, Z-52 or, otherwise. Now, your specific questions:

1) NO structural members were ADDED to a 1987 Z-51 coupe. However, some of the frame components were DIFFERENT for Z-51/52. These included the left and right forward side frame members, the front structural crossmember, and the crossmember reinforcements. For 1987, these components for Z-51, Z-52 were the same as the 1987 convertible. The convertible and Z-51/52 components were somewhat beefier and considerably stronger than non Z-51/52 coupe;

2) For 1988, it was the same as above EXCEPT that all of the above referenced components were DIFFERENT than the 1987 components. Once again, though, the Z-51/52 and convertible components were the same. Exactly how these differed from the 1987 components I do not know;

3) For 1989, different pieces were used for all of the above referenced components and these pieces were the same for both coupe and convertible and Z-51.

That's as simple as I can make it.

[tony reilly]

Re: c4 chassis frame

Thanks (again) Joe,
Simple, direct and exactly on point- can't get any better than that!
Tony