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Hello to everyone, I recently was given a 1980 4speed. The car needs some work and im excited to start the project. any recommendations on headers? Also can i add headers to stock exhaust with cat converter or was recommended? i was advised by the mechanic i need to change the rear part of the exahust system is complete rusted.
A high flow catalytic converter will do more for performance than headers with the stock converter, will be quieter and less heat in the engine compartment then with headers. I too had rusty rear y pipe. I replaced it with a Corvette Central rear y pipe and a Magnaflow catalytic converter. Those y pipes are expensive to ship. A muffler shop maybe willing to build you a dual exhaust system with dual cats. Weigh your options carefully.
Last edited by Fly skids up!; May 10, 2021 at 05:05 PM.
My 80 4-speed has sidepipes. If that's an option for you, at least consider it.
Otherwise, the 80 (and 81) 4-speed is unique in that it has a removable transmission crossmember. All other 4-speed crossmembers are bolted in. Why does this matter? You will need to remove the current crossmember to either modify it, or replace it with aftermarket, if you want a proper true-dual exhaust with limited bends. The stock 80 crossmember only supports a single pipe on the passenger side.
If you want headers, with or without two high-flow cats, you'll need the replacement crossmember, and a bunch of exhaust work. Probably $1500 to $2000 to do it correctly. And then all the pieces will still be in the way of your rear differential, if you ever need to work on that.
And that's the brief story of why my 80 has cheap used sidepipes from Craigslist.
Please post some photos of your ride!
Last edited by Bikespace; May 10, 2021 at 06:37 PM.
They are a relative bargain for ceramic coated headers, and I don't notice any difference in under-hood temperature compared to the stock manifolds. The ceramic coating could be a little better and I do not anticipate on these lasting as long as a set of top quality stainless headers, but for the money I feel like they are an excellent bargain. They also installed easily in my driveway on jackstands.
I had a muffler shop connect my headers to a 2-into-1 pipe, delete the cat, and connect it to my existing Magnaflow cat-back setup for about $235. I added a set of copper exhaust gaskets as well and haven't had any issues with leaking. So, all in all I have about $600 in my header setup. Sure, I would eventually like to have true duals, but as I said this is a good deal for the money and a noticeable improvement over stock.
My 80 4-speed has sidepipes. If that's an option for you, at least consider it.
Otherwise, the 80 (and 81) 4-speed is unique in that it has a removable transmission crossmember. All other 4-speed crossmembers are bolted in. Why does this matter? You will need to remove the current crossmember to either modify it, or replace it with aftermarket, if you want a proper true-dual exhaust with limited bends. The stock 80 crossmember only supports a single pipe on the passenger side.
If you want headers, with or without two high-flow cats, you'll need the replacement crossmember, and a bunch of exhaust work. Probably $1500 to $2000 to do it correctly. And then all the pieces will still be in the way of your rear differential, if you ever need to work on that.
And that's the brief story of why my 80 has cheap used sidepipes from Craigslist.
Please post some photos of your ride!
I want to keep it stock for now with the rear mufflers. Pics on the way ! Be aware the vehicle needs work interior and paint.
replace the cat with rear dual exhausts first. you may need a crossmember that will allow exhaust to fit past. that one can be modded with a saw and a welder... headers next. somewhere in there get the timing set right. body looks pretty good. paint most of the way stripped. car was free. it is only a 10-12k car tops. this guy is a candidate for a maaco paint job.
Last edited by derekderek; May 11, 2021 at 03:31 PM.
Like I said previously I don’t know much about cars, by rear dual exhaust you mean a total of 4 mufflers ? It currently has two , which I was told is completely rusted and no good.
The stock 80 exhaust is two into one into two. Two restrictive exhaust manifolds with 2" outlets. Two pipes, one of which snakes around the transmission. A Y-pipe that combines them and forces the exhaust through a single old-style catalytic converter (often clogged after 40 years), a single pipe under the crossmember, then another Y-pipe to separate the exhaust into the two mufflers.
A true-dual exhaust will have two pipes all the way through that do not join, so each head (4 cylinders) feeds a separate pipe, cat (if equipped), and muffler. Some people add crossovers or H-pipes, but at no time is all of the exhaust going through one pipe.
If you have to replace your 2 into 1 into 2 system because it is rusted out, there's no reason to keep the restrictive stock system.
EDIT: Corvette Central has some options. Shown only as an example, their 82 system might fit, but uses shorty headers, no cats, and may only work with automatics.
The stock 80 exhaust is two into one into two. Two restrictive exhaust manifolds with 2" outlets. Two pipes, one of which snakes around the transmission. A Y-pipe that combines them and forces the exhaust through a single old-style catalytic converter (often clogged after 40 years), a single pipe under the crossmember, then another Y-pipe to separate the exhaust into the two mufflers.
A true-dual exhaust will have two pipes all the way through that do not join, so each head (4 cylinders) feeds a separate pipe, cat (if equipped), and muffler. Some people add crossovers or H-pipes, but at no time is all of the exhaust going through one pipe.
If you have to replace your 2 into 1 into 2 system because it is rusted out, there's no reason to keep the restrictive stock system.
great explanation sir , I was able to visualized and it makes sense now , thanks again. What are the benefits of the 2 system compare to the 2 into 1? Also does the 2 system make the vehicle louder ? Is it recommended to keep the cats on the 2 system ?
great explanation sir , I was able to visualized and it makes sense now , thanks again. What are the benefits of the 2 system compare to the 2 into 1? Also does the 2 system make the vehicle louder ? Is it recommended to keep the cats on the 2 system ?
The dual exhaust is less restrictive. People add h-pipes or crossovers for other benefits at high-RPM, but basically a better flowing exhaust will support more horsepower.
A 2 1/2" exhaust is less restrictive than a 2" exhaust, and shouldn't cost much more. Long tube headers will also support more HP than the shortys (and certainly more than the stock manifolds).
The true dual systems available from the vendors are based on the 74 and earlier cars. None will come with cats, but you can add them. A PO converted my 79 to true duals, complete with two cats. The car isn't "loud" by muscle car standards (go to a cars and coffee to listen to loud cars), but you know it's there. At some point, I'll upgrade the 79 to high-flow cats, and a 2 1/2" system all the way through. But what's there works fine for now.
Last edited by Bikespace; May 11, 2021 at 05:08 PM.
Here's a photo of the 79. The cats sit under the seats (the floors are steel in later C3s to support cats), but it is still a fairly restrictive 2" exhaust. You can see how it snakes through the two holes in the transmission crossmember (there's just a single notch in the 80, but is removable). Bonus photo of my 79 with one cat.
The “test pipe” I bought from eBay was like 50.00 and was a direct bolt on , take the restrictive Catalytic Converter off and bolt the test pipe aka straight pipe in . Quick and easy , it does get a little throaty’er but not much louder though it does add power and would give you some time to think about what you really want before you make a major purchase on exhaust system . My stock white L82 is getting the test pipe installed soon , I had the test pipe in my black 80 L82 but changed it out for side pipes and headers
duals with cats? do you get emissions inspected on 80's cars in your state? as much as it is technically not allowed, most of us have no cats under our 75-82 cars. and cats aren't needed for proper performance. and aftermarket cats are a joke. california is one state everything 75-newer has to pass emissions both visually and with a sniffer. but there are other states. but for the most part, emissions test consists of plugging the code reader into the obd2 port. cars 95 and older are considered too scarce to bother with. and most of these cars, like ours get very little actual use. 92 accords and camrys are about the only 30 year old cars that can take 15k a year every year.
Last edited by derekderek; May 15, 2021 at 05:15 PM.
duals with cats? do you get emissions inspected on 80's cars in your state? as much as it is technically not allowed, most of us have no cats under our 75-82 cars. and cats aren't needed for proper performance. and aftermarket cats are a joke. california is one state everything 75-newer has to pass emissions both visually and with a sniffer. but there are other states. but for the most part, emissions test consists of plugging the code reader into the obd2 port. cars 95 and older are considered too scarce to bother with. and most of these cars, like ours get very little actual use. 92 accords and camrys are about the only 30 year old cars that can take 15k a year every year.
Im in florida, Im more concern about the loudness. Will it be louder with no cats? And also any fume smell ? Would you recommend high flow cats?
1980 headers
