I want to run better performance exhaust on my 84 5.0 AOD, but the catalogs Ihave only list shorty headers and off road H pipes for 86 on up. Why is that? I guess I don't understand why they would fit an 86 and not an 84. Anyone have any ideas on what I can do?
Thanks,
Matt

 

the headers are only listed for 86 and up because they won't line up with a pre-86 stock mid-pipe.

here (from bbkperformance.com):

Q. The 5.0L shorty header system lists as only for 86-93. Can I use it on my 1985 or older mustang?
(part numbers affected include: 1515, 15150, 1512, 15120) A. The shorty systems are fully capable of being used on 79-85 mustang engines. However, they are not a direct bolt-on for the remainder of the system. The 86 and ups used a dual exhaust system with an H-pipe that differed from the earlier models. If you have plans to upgrade your 79-85 mustang to the newer dual exhaust system, then a BBK shorty header upgrade would be a great way to finish off that job, and will help you make maximum horsepower from your project pony.

 

You need a new 'doublehump' cross member for use with dual exhaust. They went true duals in 86.

Also, youll need the exhaust hanger under the trans mount. Theres one for auto and one for manual.

 

And one on the drivers side rear. If you dont want to buy headers right now, just find a set of stock 86-93 headers. Might keep the stock exhaust manifolds and heat pipes in case you ever want to put it all back to stock.

 

http://cgi.ebay.com/ebaymotors/1979-...QQcmdZViewItem

theres your double hump crossmember^^^ i have the same one because my original rusted out and the quality seemed fine.

 

you have to get a new trans cross member and then you can run the duel exhaust. and the shorties will fit they are the same thing so just go ahead and get them. you cant run an 86+ exhaust till you get that cross member thats the only reason why it says 86-93. now with the cat back you have to watch it over the axel the rubber brake lines will run right against the pipes and usually have to be pulled away and tied back so you dont melt through them.

 

so the headers will work on a stock-style pipe? cuz i'm in cali... not allowed to switch to a dual exhaust. cali emissions laws make me[:'(]. but the headers will bolt right up?

 

actually you can switch to a dual as long as you just get an h-pipe with cats that are 50 state legal it should pass the sniffer test

 

they will not hook up to the stock pipes. and as 85 said you can get the h-pipe as long as you have cats in it

 

Im gettin an '84 gt350. What does the 'doublehump cross memeber and the exhaust hanger usually run for? It's an auto

tim