I just aquired a set of headers. I have two cars a 79 with stock exhaust and an 85gsl with the cats removed and replaced with a pre-silencer. My question is which car would I get the most benifits from the headers. Also what will the headers most likely do to the sound of each car. Will they cause failure of the cats on the 79? Trying to decide which car to install them on and looking for some advice and suggestions. The headers are racing beats.

Thanks in advance.

 

85.

 

The 79 doesnt have cats

 

the 85 would be your best bet and it should sound pretty decent also

 

Does it not depend on the year for which the header was made? I was under the impression that they weren't all interchangeable. If they are interchangable, I would think you could feel it more on the 85 since you already removed the cats. It should make your exhaust sound a bit louder too.

 

That's a good point. Headers for 81-83 are different than 84-85 or 79.

 

I vote for the 79 because it is lighter to begin with

 

I would put it on what ever it fits, but if you do decide to put it on the '79, you don't have to worry about cats cuz it doesn't have any. It has a heat exchanger, but it won't be a problem. Also, make sure you have all the block off plates before trying to install the header, because you'll will need them.

 

Put it on the 85. The presilenser plus the header is 2/3 a HP system. Add a RB Power Pulse muffler & you have the total system which sounds awsome. The best set up out there IMO.

 

Thanks for all the replies so far. I did not realize the headers were different for the different year models. I was under the impression that all 12a engines would use the same headers. I do believe that 79s do have cats. They do not have the 3 cats that later models have but they do have two. At least that sure looks like what is on mine. They do have the thermal reactor that attaches to the engines exhaust ports but also have two cats located between the thermal reactor and the muffler.

Based on what I have read so far, I am leaning toward the 85. My 79 has a fresh rebuild in it and right now and with its stock exhaust will easily outrun the 85. So, maybe the 85 could use the few extra horses gained with the headers.

 

I would say that it would have more benefit on the '79 assuming you can use it on either. The thermal reactor it would replace is very restrictive, more so than the exhaust manifold on the later models from what I've heard. Plus since the '79 has a fresh rebuild, why not let it breath a little better.
Just my $.02. Good luck.

 

A '79 should not have any cats. Instead of an exhaust manifold like an 81-85, the 79-80 have a thermal reactor. After the thermal reactor, the 79-80 has a heat exchanger that looks damn near identical to a cat, but its not, it a heat exchanger (which means that on a 79-80 you can still run leaded fuel [i think]). I don't know why yours would have two heat exchangers though, unless a previous owner installed cats to make it pass emissions. If you really do have cats, running a header might not be a good idea since it wouldn't get air from the airpump. You should be able to run the header on the 79 if it has a heat exchanger, but not cat(s).

 

if your 79 is running that good then i would keep adding power to it instead of trying to make the other catch up. plus, like others have said, it's lighter already so it seems to be the best choice

 

any 12-A header will fit as long as you replace the exhaust pipe to the muffler.