86+ headers on 85 GT

go to www.foureyedpride.com

the people in the forums there can answer any question you have about this swap

I have a complete 86 exhaust system on my 85. All I needed was the double hump cross member. All the existing hangers for the car were used. And the heads are different, but the exhaust ports are the same, thats why you can interchange headers. Make sure when you install the trans crossmember and after the exhaust is hooked up and the trans is remounted to the cross member that you have it (cross member) tack welded in place.

Yes the heads are different but not as far as how the headers bolt on or anything like that. 85 was the first year of the factory headers (as far as I know) and since it was carburated, you have those heat riser tubes going to the air cleaner. The 86+ headers did not have a provision for that since they are FI. There is also a little flapper valve do hickey in the passenger side collector on the 85 headers. Due to this, there might be a slight variation in the length of that header compared to an 86+ that would make it nessecary to modify the mid pipe to bolt up. I assume that the reason they dont list them as being for 85- is because it isnt considered a direct swap for these reasons and while I dont know this for sure, I suppose that there could also be emission legalaties issues involved with the removal of the heat risers. But to answer your question more directly...the 86-93 headers will bolt up to your motor and if you are using an 86+ H-pipe and cat back...no worries with the exception of needing the double hump crossmember.