School me on intake manifolds and headers

[bigcountry78]

Thanks to @Vbb199 , I now have a set of long tube headers for my truck. He and I have discussed this some but I’m completely new to the subject of add on engine accessories. So, what can I expect, real world, from a set of long tube headers, and aftermarket intake manifold, and an open element air filter? I’ve never messed with any of this. I’m not looking to smoke my tires off, but I believe my 350 only makes around 160 horsepower. I think it can do better, and some more torque for towing would be nice. It has absolutely no smog equipment, and is stock other than dual flow master exhaust. Which intake manifold will work with my Quadrajet? This truck basically needs to be daily driver capable, so I don’t want to go crazy with cams and all that. I know I will lose my heat riser tube with the headers, so I figure I might as well ditch the factory air cleaner and run an open element type to get some more air flow.

 

[Joe T]

You’ll loose a little bottom end with the headers.

Depending on the shape of the motor your dollar is better spent on doing a cam. A good mild non emissions cam.

Do these need a recurved distributor when jacking with the cam?

 

[bucket]

The factory manifolds are actually kind of bad. A set of headers are a good first upgrade and a decent set of longtubes will gain a bit of power all over, even the low end. Besides the butt dyno, it's been proven many times on an actual dyno as well.

 

[legopnuematic]

For a stock style aluminum manifold the Edelbrock 2101 is a good choice, it accepts both spreadbore and squarebore carbs, no egr, and provision for a hot air choke. An air gap style manifold can be a better choice, but you lose the use of heat riser crossover if that is important to you.

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This is my 76 with a 2101 intake, Q-jet, Summit 76cc/165cc intake runner heads, howard's CL112561-12, long tubes.

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[Backfoot100]

The headers and duals are an awesome first start.
That 2101 Edlebrock is also a good intake. You'll definitely get better throttle response.
The air filter I don't think is worth it. If you have the cold air tube from the factory air horn to the radiator support that brings in outside air, that will be more effective than an open element air filter. Taking out the factory flame arrestor, if you have one in your air filter is a huge restriction. Get rid of it if you have one.

Those mods will get you maybe 170-180HP but the throttle response will feel like more as long as you have your carb and ignition tuned well. It'll definitely be noticeable.

At that point you're at about the best you'll get out of the factory heads. An internal combustion engine is an air pump. Its only as good as it's most constrictive bottleneck in the overall air flow from the carb, intake, heads and exhaust. At this point, the factory QJ is more than adequate. You'll have opened up the intake and exhaust so your next bottleneck is the heads. A cam will wake it up a little more but not enough to to justify the work IMHO.

You upgrade the heads and then add a cam and you can easily tweak an honest 300 HP or a little more out of that motor.

I see these same mods on a regular basis in small block marine engines with excellent results.

 

[4WDKC]

Changing from restrictive intake manifold and exhaust will cause the engine to be leaner than it was an will require adjusting the carb to correct. Any time you change the cam you should check the timing and make sure it matches the timing curve of the cam to be optimized.

 

[shiftpro]

The factory manifolds are actually kind of bad. A set of headers are a good first upgrade and a decent set of longtubes will gain a bit of power all over, even the low end. Besides the butt dyno, it's been proven many times on an actual dyno as well.

As Joe mentioned above, you lose bottom end power a bit with 1, shorty headers. 2, large diameter tubes. 3, exhaust tubing over 2.5 (small block).
So the OP has longtube headers he is in the right track.


Any dual plane intake would be better than the stock battleship.

 

[shiftpro]

Changing from restrictive intake manifold and exhaust will cause the engine to be leaner than it was an will require adjusting the carb to correct. Any time you change the cam you should check the timing and make sure it matches the timing curve of the cam to be optimized.

Most of the time they are running too rich already so the new leaned out mix is welcome.

 

[bigcountry78]

The headers and duals are an awesome first start.
That 2101 Edlebrock is also a good intake. You'll definitely get better throttle response.
The air filter I don't think is worth it. If you have the cold air tube from the factory air horn to the radiator support that brings in outside air, that will be more effective than an open element air filter. Taking out the factory flame arrestor, if you have one in your air filter is a huge restriction. Get rid of it if you have one.

Those mods will get you maybe 170-180HP but the throttle response will feel like more as long as you have your carb and ignition tuned well. It'll definitely be noticeable.

At that point you're at about the best you'll get out of the factory heads. An internal combustion engine is an air pump. Its only as good as it's most constrictive bottleneck in the overall air flow from the carb, intake, heads and exhaust. At this point, the factory QJ is more than adequate. You'll have opened up the intake and exhaust so your next bottleneck is the heads. A cam will wake it up a little more but not enough to to justify the work IMHO.

You upgrade the heads and then add a cam and you can easily tweak an honest 300 HP or a little more out of that motor.

I see these same mods on a regular basis in small block marine engines with excellent results.

I don’t have the cold air duct, I just have the small tube that kind of sticks out there over the engine. I thought an open filter might at least flow more air, even if it is hot air. Like I said I’m completely new to all this. You can see the bottom of my air filter housing, and the little tube off to the left.

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[Frankenchevy]

the performer EPS and street warrior intake manifolds are the newer computer designed offerings. both are supposed to be better for low-mid than say the performer rpm or stealth warrior. the port shape is improved among other things. they've tested this stuff, not a huge difference between eddy and weiand across the different dual plane models.

 

[82sbshortbed]

I got this one and know its better than stock. Lol and looks better too. Don't quiz me on stats.

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[Backfoot100]

I don’t have the cold air duct, I just have the small tube that kind of sticks out there over the engine. I thought an open filter might at least flow more air, even if it is hot air. Like I said I’m completely new to all this. You can see the bottom of my air filter housing, and the little tube off to the left.

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Then I agree that a new open element filter will help.

I'm pretty much the same as you. Totally stock except headers and duals, a carb rebuild and some tuning of the carb and timing.
Only difference is my air cleaner is the tall 5.5" one with the cold air intake which I kept and just put in a K&N filter. It also had a flash arrestor which I removed.
I have a Performer Air Gap manifold that I haven't put on yet.

So far everything I've done has made a noticeable difference. It'll at least get of its own way now which was never the case before.
I plan on installing the intake this winter after it cools off. Still too flippin hot to do that now.

 

[4WDKC]

I don’t have the cold air duct, I just have the small tube that kind of sticks out there over the engine. I thought an open filter might at least flow more air, even if it is hot air. Like I said I’m completely new to all this. You can see the bottom of my air filter housing, and the little tube off to the left.

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I read somewhere on a stock engine the additional flow of hot air is no improvement over the stock restrictive cold air setup, it just sounds like it is.

 

[Backfoot100]

I read somewhere on a stock engine the additional flow of hot air is no improvement over the stock restrictive cold air setup, it just sounds like it is.

+1
I gotta believe the factory CIA is about as good as you can get. Purely IMHO.

 

[4WDKC]

+1
I gotta believe the factory CIA is about as good as you can get. Purely IMHO.

I wouldnt go that far but, better than open element sucking in hot air. Ther eare other better options just not cheap for GMs mass production use.