86+ headers on 85 GT

[buckster_03]

I was just wondering if the heads for a 1986 mustang 5.0 were the same as the 85 gt 5.0. The reason for the question is because I end up seeing alot of aftermarket headers for the 86-93 years but nothing for 85 and before. I would think if the heads for each car were the same then you would be able to use 86 headers on an 85. Also if I do end up using an 86 header setup would I be able to go with 86+ h-pipe and aft-cat setup considering (from what ive seen and heard) that the exhaust setup for the 85 and lower is from a split single exhaust and cat . It looks really tight and awkward to get the setup im looking for in there. I have never seen the underside of an 86+ but i would assume it would be pretty similar. If this is the case it would certainly free up alot of airflow restrictions and probably boost up hp (an sound) very nicely . Any suggestions of how to make this work would be greatly appreciated. Thanks

1985 Mustang GT 5.0
Completely Stock!!

 

[buckster_03]

hehe i pretty much answered my question when it comes to using the h-pipe and aft cat setup from 86+ for the 85 and before. You need a transmission mount from a 86+ mustang much like this:

http://secure.50resto.com/product1.cfm?SID=1&Product_ID=89&Category_ID=987

now all I need to know is if the 86+ headers can be used for my gt!

1985 Mustang GT 5.0
Completely Stock!!

 

[5 Liter Mustang]

go to www.foureyedpride.com

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

 

[Fishhawk]

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.

 

[MrKwik]

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.

 

[buckster_03]

This is what i thought was the case. I knew it was different but still believed that they would still work. All I REALLY need is the trans cross member to make the swap. Thanks for your help guys.

1985 Mustang GT 5.0
Completely Stock!!