'81 Exhaust - Hooker Headers

[gedmeyer]

I'm starting to lean towards getting my exhaust done for my '81 with a 383. Currently, I'm running a stock exhaust. I have spent a good deal of time going through a mind numbing number of threads about exhaust, but at this point, it'd probably be quicker just to ask.

I would like to get a good set of headers (ceramic coated) and run true duals to a good set of mufflers out back. I plan on using stainless steel for the pipes and mufflers.

How are these Hooker Competition Headershttp://store.summitracing.com/partdetail.asp?part=HOK%2D2456%2D1HKR&view=257&applid=%7BA3C1586B%2D495F%2D42AA%2D85D4%2D367A6344F96C%7D)
Does anyone have experience installing them? I've got a 4spd with A/C.

Next question, what's the best approach for the rest of the piping? I was thinking 2.5" all the way back with some kind of crossover. Would it just be prudent to get everything done at a local shop? I can't weld myself.

Thanks!

 

[81 Corvette]

i went with dynomax ceramic headers. I don't know if hooker is better or not, but i'm budget minded. That said, I love em. They sounded sooo sweet before the exaust was bolted on.

Install is a breeze on an auto, but i'm not sure how a manual tranny will affect it. I'm sure someone can answer that. Plan on 3 hours.

I have flowmaster 40's on the rear. I like the sound. Not to bad on the inside, but when you stand at the rear of the car, you can really hear them and feel the ground vibrate.

No matter what header you choose, its an absolute must to get high quality gaskets and bolts. I put on the gaskets and bolts that came with the headers and less then a week after install, i'd burned one gasket up and had bolt after bolt coming loose. Percy's dead alluminum and stage 8 locking bolts took care of that problem.

here is some info from my install
http://corvetteforums.net/eve/ubb.x?a=tpc&s=1196032491&f=5026032691&m=8586048163

 

[gedmeyer]

I see that the dynomax ceramics have been popular too. Is 2.5" pipe the right diameter for the rest of the system?

As for the mufflers, I DEFINITELY want a strong sound, but I don't want to deal with resonance in the car. I do drive the car regularly and I do not want to have my ears ringing after every time I drive (not to mention being able to talk to ladies I'm trying to impress with the car! ) Also, I want to make sure the muffler fits right underneath. I would like the back end to appear completely stock.

 

[81 Corvette]

Lets just say, with the 40's and the windows down, forget about trying to have a conversation on the highway. Mostly wind noise tho. With the windows up, it’s not too bad. Personally, I really like the 40's. You can defiantly hear the exhaust at a stop light with the windows up or down, but interior noise isn't bad, but the sound when standing to the rear of the car is excellent imo.

I just did a quick side by side comparison of the headers, and I did notice that the individual pipes take different routes from the exhaust port to the collector. But I'd be clueless as to which is better.

I'm sure someone will chime in with a diameter opionion. I'd say 2.5 is enough, but to be honest I don't know.

As a side note, have you thought about side pipes? In a way, I kind of wish that I would have went this route. The total cost with headers and pipes look to be comparable. Only bad thing is leg burns and the noise.

 

[Robin7TFour]

Ged, i would like to add my 1/2 cent. have you thought about a chambered exhaust? a mellow sound really nice tone at slow speeds ,but barks when you nail the throttle.
my sidepipes are chambered and was quite suprised they were as loud as i was expecting. i am sure the out the back would be even better,since they won't dump right next to your ear

Robin

 

[curtis]

running Hookers on my 76 4-speed.Easy install, but if I remember right the right side had to go in from the bottom. ASk Summit about Hooker mandrel bent dual exhaust. Mine fit nice. No welding.

 

[Vette/Berlina-coupe]

Ebay to the rescue....

-here's a source i found on Ebay whereby you get a beautiful pair of Holley/FlowTech's(BowllingGreen, Ky.) silver-ceramic inside/outside-coated 16-gauge/Headers made just for pre-C4-Vettes (click on pix below), ---for $200 !!! (-say you're from CAC-forum, -that may even include shipping!)
contact Seller(MikeWaller): " headersforless@hotmail.com "
~Bob Vonheck (have NO association, -am awaiting shipment of my order; --later: -the pair just arrived, they certainly appear to be very nicely made, clean welds, and the sweep-back formations actually look nicer than Hookers!) Note also, that if you fabricate an H-pipe proximal the tailpipes attachment point (close as possible), it will quiet-down any adverse 4-cyl.-throbbing sound, -whereby you'll hear a smoother 8-cyl's. from each pipe instead of a cobbly-sounding 4-cyl's. !!

 

[CyberVette81]

I just installed Hedman HTC ceramic coated headers, removed the cat, ran true duals and ended with SS Magnaflow mufflers. It is a great set up. Sounds sweet and improved the performance. This car sounds the way a Vette is supposed to. Hedman was the first company to come out with the ceramic coat so the quality is top notch. Hooker is a great brand but kind of pricey.
I actually did not do the work myself. I had an exhaust guy do the installation. He ran 2-1/4 pipe and said 2-1/2 would actually diminish a little HP. Just my 2 cents. Good luck with the change.

 

[AKRAY4PLAY]

how is your motor built?? a mellow build will do better with 2 1/4" exhaust, and a higher HP build will like the 2 1/2" duals. Headman, Dynomax, Hooker, etc. are about the same except for the price. i had Dynomax headers in my dual system, no complaints. you may want to look at the Dynomax Ultra Turbo Flow mufflers. they are stainless and fit better than stock. the sound is deep and soft at idle and cruising speeds, a little loud at wide open throttle, but nowhere near as obnoxious as Flowmaster 40's. remember the old police cars of the early 70's?? that is the way the Ultras sound. i think they will suit your needs perfectly. mid-pipe kits are getting harder to find, so an exhaust shop may be cheaper than ordering a kit. Brian

 

[gedmeyer]

My motor is a 383 stroker now. The basics: stock heads, 9.6:1 compression, Comp Cams Magnum 270H cam. The engine should be in the mid 300hp range. I don't know if I would call it a higher HP build, but it isn't mild either.

As for the old police car sounds of the early '70s... Can't say as I had the pleasure of witnessing any of the '70s! (I'm a young'en)

To spread out the cost a bit, I am debating getting the headers this summer and just adapting them to the current exhaust. Then I can finish the job in the spring or early next summer.

 

[Bob Chadwick]

I have the Flowmaster Delta 50's with Dynomax headers. I went with 2 /14 inch pipe becuase of the low HP of the car. I was told that this size was good up into the high 300's. Any bigger with my setup and I ran the risk of loosing low end torque.

Good sound with just the slightest amount of resonance at around 1,500 rpm.

 

[AKRAY4PLAY]

Tim,

with that build i would lean to 2 1/4" exhaust. it will give you better throttle reponse and more low end torque. clearing the rear diff is an added bonus of smaller pipe. if you plan on replacing the heads and turning the motor to 6000 rpm, then look to the 2 1/2" system. as for mufflers, i like the Dynomax Ultraturbos. they flow about double what Flowmasters are rated for with a more mellow sound. Flowmasters will give a good muscle sound, but they are more prone to resonate. either way is a far cry better than stock. Brian

 

[81 Corvette]

as for muffler noise, I had someone at work comment that they could always tell where my car was.

I still don't think its too loud in the cockpit, but maybe i'm just deaf

 

[Fishman]

I have the Hooker Super Comp cermanic coated headers, true-dual 2.5" pipes, and Flowmaster 30 Series mufflers. On the front end is the ZZ crate motor with loads of power. It all seems to work well together.

 

[Space Cowboy]

I contacted Hot-Jet directly and ordered a set of Hooker Super Comp. 3" and had them apply they're process. The set shipped in a week ago and THEY ARE SEXY! They're not called Hookers for nothing! LOL! I can't wait to get them in with the new block.

 

[dirtypants]

what headers or ex manifold for my 81 with ALL smog removed?

My 81, 350, man trans has all the smog removed..no A.I.R., no egr, no computer, no catalytic, no oxy sensor (running Edelbrock carb, intake and cam)..the left ex manifold has a crack..so time to replace em. What will fit? With all the smog stuff gone..will an earlier vette ex manifolds fit (79-80>) ..what "year" of aftermarket will fit..(cuz the 81 manifolds have all the A.I.R. etc that I do not need.) I don't need to spend a ton on race headers..but I do already have true dual exhaust with Flowmaster mufflers..What header (exh manifold) do I shop for..to fit. Are gaskets to head the same as earlier year..say 79-80? Thanks,
Nick

 

[Tom Bryant]

1981 was the first year for tubular exhaust manifolds (shorty headers) and they used a gasket to the heads. If you use anything earlier it will be a cast iron manifold and will not use a gasket. Not sure if they all had emissions tubes. You may have to go back into the mid 60's reproduction manifolds. Some run around $129.00 each; others much higher. Swap meet ones will probably need new studs and cleaning. You also need to be sure if you need 2 inch or 2 1/2 inch outlet to match your existing head pipes. On the up side is that they fit in the same place that the tube manifolds came out of. There will be no difference in performance to what you have now.

If you want headers. I see Summit offers some mid length headers that might be a better choice for street with more ground clearance than long tubes. They are lower cost than repop iron manifolds but will require some front head pipe modification. There are some good copper header gaskets and locking header bolts available now that are pretty much leak free, so they say.

Tom

 

[dirtypants]

anyone with an 81 replaced ex manifold/headers?

Thanks Tom..I will do some checking and measuring. Anyone out there that has replaced exhaust manifolds/headers on an 81, std trans...?? If so..any info appreciated as to what you used and how it fit up.
Nick

 

[Bob Chadwick]

I had the copper gaskets and Stage 8 locking bolts on my 77. Worked like a dream.

 

[dirtypants]

dont know what i dont know about 81 exhaust manifold

Thanks for info thus far, I am keeping notes, BUT.. I am finding that I don't know what I don't know..so I don't know if the ports on the 81 engine line up with all or most prior year or after market exhaust manifolds or headers made for any year 350. Don't know if there are fitting/clearance issues in various exh manifolds in the install..don't know if there are things to pay attention to in alternator, Air Cond compressor, etc in manifold clearance or fitment...and don't know since I don't have any smog equip on car can i plug up manifolds that come with A.I.R hole, or will prior ones without fit OK..Since the usual parts source catalogs do not list manifolds for the 1981..can I just bolt right in, say an 80 or a 79 exh manifold..or headers made for a 80, or 79..or even prior? or even if way back..60s or 70s..for a 350?

Anyone out there that has replaced exhaust manifolds/headers on an 81, std trans...?? If so..any info appreciated as to what you used and how it fit up.
Nick[/QUOTE] I'd love to hear from an 81 owner..and even better with A/C and 4 spd..that has installed manifold or headers.
Thanks
Nick