Headers or iron manifolds?

[99xcss4]

My 97 350 has all 4 sensors in the y pipe.

yes all 96+ gmt400s the o2s are in the pipe. the 87-91 r/v square body tbi and the 88-95 gmt400 tbi are not the case. my 454 tbi o2 is in the y pipe. all of the 305 and 350 tbi engines that I have seen the o2 is in the manifold and I would think the v6 was the same. I was asking if the 305 and 350 tbi engines ever had the o2 in the y pipe like on my 454.

 

[Moofus02]

yes all 96+ gmt400s the o2s are in the pipe. the 87-91 r/v square body tbi and the 88-95 gmt400 tbi are not the case. my 454 tbi o2 is in the y pipe. all of the 305 and 350 tbi engines that I have seen the o2 is in the manifold and I would think the v6 was the same. I was asking if the 305 and 350 tbi engines ever had the o2 in the y pipe like on my 454.

I've got 2 95 tbi 350's and the o2 is in the pipe after the y. I think all my 5.7's were like that. Maybe my 88 with air injection manifolds and air pump had it in the manifold but that was a long time ago and I don't remember

 

[Supercharged111]

Definitely things to learn with a dyno and usually equals more questions than answers. I remember a test where an intake extenstion was added to a GenIII Hemi. It added a big chunk of torque having snuffalopagus on the front of the throttle body. Impractical for any kind of vehicle except maybe an air boat or jet boat, but wild to see. The reality of an engine is that anything from the air inlet of the air box to the outlet of the tailpipe can effect the torque curve and output. Seeing that intake tube, made me wonder how much a 90* bend close to the throttle body would change the output.

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Rookie stuff.

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[Schurkey]

I installed Gibson shorty headers and absolutely love the difference in how my rig drives, it feels as it's a different truck.

BTW, don't install a paper gasket, upgrade to a copper gasket. I removed the iron manifolds and the paper gaskets were all disintegrated and fell apart. Also, upgrade the hardware to stainless APR manifold bolts...just my .02 cents.

Edelbrock shorty headers (TES--Tubular Exhaust System) on my '88.

Didn't make any "real" difference on my truck. I was disappointed in the lack of added performance.

If you do install headers, buy the spark pug spacer kit

Link? Photos? I have no idea what this is.

Maybe my 88 with air injection manifolds and air pump had it in the manifold but that was a long time ago and I don't remember

My '88 K1500 5.7L has the air pump. Yes, the O2 sensor is in the left exhaust manifold. Friend had an '89 K1500 5.7L without air pump. O2 was also in the left manifold.

Educated guess: One-wire O2 sensors were in the manifold. Heated O2 sensors were in the pipe, farther downstream.

 

[99xcss4]

my 94 454 is one wire in the y pipe just after the merge

 

[Komet]

If you took those Sky Ram runners and crossed them across the valley, then smoothly curved them back into a common plenum, I bet it would fit under the hood easier.

Not sure where you'd find a setup like that though. Certainly not on mid-late 80's sports cars. Who would put a truck intake on an application like that?

 

[GoToGuy]

The general consensus has been that shorty headers are not worth the hassle. However, some swear by them. If you are already replacing cracked/warped manifolds then maybe it makes sense.

A properly sized and plumbed single exhaust will always make more power and torque than a similar dual exhaust, no matter the vehicle or engine.

Most have reported a greater gain with a less restrictive y pipe than by switching to shorty headers.

Where did you get this information, is there some testing your aware of, if so post it.
What " general consensus" are you referring to, how do support that statement? Car club, research lab, OE testing or personal experience, mail in ballot.

What is your reference for " properly sized and plumbed " single exhaust. Your statement sets the bar for perfect single exhaust, versus a similar dual , will the dual be properly sized and plumbed, placing them on an even scale for testing?

 

[Road Trip]

Rookie stuff.

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Mighty tall intake on that dyno. The resulting torque curve plot was neat to see. Love it
when induction theory comes to life when dyno runs like this are videotaped for our enlightenment.

Same as it ever was -- Check out "The HIGH & MIGHTY" that the Ramchargers (a group of young Chrysler engineers back in the late '50s)
put together:

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(credit: Secrets of Chrysler Ram Induction -- link HERE)

If you took those Sky Ram runners and crossed them across the valley, then smoothly curved them back into a common plenum, I bet it would fit under the hood easier.

Not sure where you'd find a setup like that though. Certainly not on mid-late 80's sports cars. Who would put a truck intake on an application like that?

Komet, I read your TPI build with great interest, for I actually have a complete L98 under the bench, and
would love to find an early RCSB GMT400 that needs repowering. I would enjoy the challenge of
building a complementary, carefully tuned exhaust setup, and end up with my own 355SS.
(And keeping the '99 C2500 of course, no replacing that. :0)

Anyway, your comment reminded me of the old Chrysler 413 equipped with the crossram 2x4
induction setup:

"Sonoramic Commando" -- kinda just rolls off the tongue, doesn't it?

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(credit: Secrets of Chrysler Ram Induction -- link HERE)

EDIT: For a short technical article on the underlying principles, here's a great .pdf file: http://www.chrysler300club.com/tech/ram.pdf

So many super trick powerplants over the years...

 

[Rock Hard Concrete]

Exhaust scavenging and flow are best with a single exhaust. Now of course, it may be easier to build a good flowing dual exhaust in a vehicle with restricted space for a proper merge point, size, bends, etc for a single exhaust. I correct my original statement since some vehicles may not support a single properly, even though the engine would technically flow better with one.

As far as shorty headers vs manifolds I should have extrapolated that most of what I have seen from surfing this forum for 8 years is that people were getting better gains for the money by upgrading the rest of the stock exhaust rather than just shorties.

 

[Komet]

Komet, I read your TPI build with great interest, for I actually have a complete L98 under the bench, and

would love to find an early RCSB GMT400 that needs repowering. I would enjoy the challenge of
building a complementary, carefully tuned exhaust setup, and end up with my own 355SS.
(And keeping the '99 C2500 of course, no replacing that. :0)

That sounds like a great build idea! One of the things that really turned me on to TPI was drivability, which is one of the nebulous qualities people boast about when their setups don't make power, but it does really have a lot of low speed responsiveness because of just how early that manifold builds torque. My IROC-Z when fully warm will drop into overdrive going up a hill at 1200rpm and it's totally fine. Stab into the throttle at any time in any gear and the rpms come right up with a big smooth wave of torque. Which is sorta replaced by noise and disappointment by 5500rpm, but hey in a truck that's redline. It cruises awesome, basically, and the data supports it:

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TPI makes a lot of power below 3000 rpm on a stockish 350, and you can feel that efficiency all the time.