open header question

[thachevythang]

I'm tired of my glasspack/resonator tips and my stock exhaust manifolds need to go! Waiting until my LQ9 swap is complete, I was planning on running some cheap headers without exhaust. I'm registered as a classic in TX so emissions stuff isn't an issue.

I'm looking at these cheap ones from summit: http://www.summitracing.com/parts/SUM-G9006/

Are there any downsides or issues while running open headers?

Going on a 350 with cam and intake. They will stay with the 350 until swap is complete and they fall off!

[1979C20]

Open headers are LOUD. And you get a lot of backfiring, even just letting off the gas. The backfiring can burn up your valves and blow your gaskets. I know from experience. Haha. But, when I first rebuilt my engine, the stock exhaust had a lot of leaks and terrible power. I got a set of headers and before I bought my glasspacks, I ran open headers for a week and a half. I ended up nearly rupturing my left ear drum, I got terrible gas mileage and acceleration do to lack of back pressure, and the backfiring sounded like gun shots(manual trans). I wouldnt drive at night. I felt rude to the sleeping neighborhoods. So, if anything run straight pipes with no mufflers but run them full length.  Also, even bolting just the collectors to the headers made them quite a bit quieter. My .02¢

[bake74]

     I agree with everything 1979c20 said, your not going to like them if you run them, and you have the chance to ruin your valves on a rebuilt engine.

[choptop]

Registered classic or not, open headers will bring you to the attention of the law, and just because it doesnt have to be inspected with the classic tags, it is subject to inspection if it is brought to someones attention. It is illegal to run open exhaust on the street. We have to be careful with the classic tags, it is an option that can be taken away from us if abused. Just some cheapy mufflers or glasspacks will work until you get the engine swappeds and youll thank your ears for it as well. Open headers sound ok at the drag strip, not the street.
  Also understand that the LQ9 will void your qualifications for the classic tags. The engine has to be 35 years or older as well as the truck. No they dont check but its another reason not to bring attention to yourself wrecklessly. They can get you if they want to just depends on what kind of mood the officer is in at the time.

[thachevythang]

I knew it would be loud but didn't know it would be more annoying than the glasspacks!

Local law enforcement not a big deal. I work with the sheriff, he's my next door neighbor. All the deputies and I get along and me and one are building on his truck. Same with DPS troopers. Ones a friend I grew up with and the rest all know me or come over for beers on the weekend  . Benefits of super small town Texas!

Thanks for the pointers. Didn't know that the swap would void the classic status. I only drive it locally now but once the swap is in I plan on longer trips.

I've seen these before but figured ehhh going a different direction. Anybody have opinions on these? http://www.stylintrucks.com/part.aspx?category%7ccategory_root%7c-28=Performance&category%7ccat_-28%7c161=Exhaust&category%7ccat_161%7c1021=Exhaust+Systems&canned_results_trigger=&partfamilyid=6320&partid=599643

[jackjeckel757]

I have never run open headers, but I am running headers with straight pipes and no mufflers with my 305.  The sound isn't loud till you get on it, highway and street cruising are fairly quiet but when you hit the gas it gets pretty loud especially when the 4 barrel opens up.  I have heard louder on cars and trucks with mufflers!  Maybe you could get those electric 2 way diverter pipes that let you go between open headers and whole exhaust with the touch of a switch.

[acefoxx]

The back fireing isn't the only damage you can do to the valves. A lot of the racers at the track that run open headers will stuff a rag in them when they shut it off so the cooler air doesn't flow up and warp the hot valves.

[team39763]

ChopTop is 100% correct.

I did the swap on my truck.

An officer who was online pointed me towards a site that stated the law differently and made no mention of the age of the engine.  At the same time another site did mention it.  I printed out a copy of both to keep in my truck.  Trust me it'll come in handy...it helped me out of an issue a while back.  One argument that might work with some officers is stating that your LQ9 is a smallblock chevy...which GM has been using for the last 50 years...it just has a newer ignition/fuel system.  Your best be is to not call attention to yourself and don't give them any reason to look under your hood.

[Grim 82]

Open headers would make for a miserable driving experience IMO, and if there is a chance that you could do damage to your engine, it seems worth it to run at least some kind of exhaust system.

Also if you order those headers don't forget to order the bracket for your p/s pump, unless you are going to make one or you already have one.

[TexasRed]

I ran open headers, down to get them matched up with the exhaust system that was cut. It was super loud. Driving down bingle in Houston was nerve racking. The truck being off or open headers are the only time I can't hear the electric fuel pump, LOL.

[VileZambonie]

I would rather walk than daily drive with open headers! Leave it alone

[Irish_Alley]

I got open headers on my 79 with historic tags like your classic and with a 350 the sm465 helps creep out of dui/seat belt check points but if they ever do ask me about them the passengers side exhaust fell off so I cut the drivers side so it wouldn’t run uneven  but my truck aint my dd and like vile said I wouldn’t drive it if it was. I just drive her once twice a week get hay or just cruse and want to make some noise AutoZone sells cheap mufflers in the back I think when I worked there they were like 20 a pop

[okiewelder1973]

yep, i burned my valves doing that same exact thing...you're only 18 once

[1979C20]

yep, i burned my valves doing that same exact thing...you're only 18 once

haha. Im 17, and rupured my eardrum with open headers. I dont want to know what I might do when im 18.

[thachevythang]

Thanks for the input guys!!! I really didn't know any damage could be done running them open.

Not getting them now anyways! The 350 was supposedly rebuilt by my dads friend with only like 800 miles, but I'm getting smoke out of the passenger side exhaust now. Starting to backfire as well. I was told it could be blow by.

The only thing I've done to it was the intake and carb. The cam swap was done by a buddy of mine. Was taking a crack at rebuilding a 305 to replace a strait 6 in my 56 bel air. It was originally in the truck but looks like its going to be put in for a while or the truck is going out of commission for a good while.