I am curious as to whether or not the header panel from a Cutlass Ciera will fit and line up properly on my 1986 Firenza. Just from an eyeball inspection it appears to be very close. I was looking at a 1991 Ciera that is being parted out and prefer the looks of it's header panel as compared to the one on my Firenza.

I'm only guessing, that it probably won't fit. The A-body is wider than a J-body. That doesn't mean you can't make it work, with enough fabrication skills. But it would require a good bit of cutting, molding and shaping on both the inner and outer panels.

Thanks for the reply. I need to do some actual measuring on both cars. I didn't think the FWD A body was any wider than the J bodies. It may turn out to be way more trouble that it's worth.

Yeah the A-body is around 4.5" wider. Pretty sure the header panel would be wider than a J-body. And the front of the fenders appear to be more rounded on the 91 Ciera too. Kinda like the difference in the 1st to 2nd gen J-body.
It would be a good bit of work to modify it. And of course your Firenza would be out of service until you got everything swapped. You'd need to remove the Firenza header while you worked on shaping the Ciera header.
It would be a cool project though.