Affordable Headers

[kennythewelder]

I do not! I saw a big header comparison on the same 350 Vortec engine about 10 years ago. Same primary diameter. Same collector diameter. Only difference was short vs long. Same exhaust piping and mufflers were used as well. The shorties had a very narrow rpm band in the 4,500-5,000 rpm range they out performed the long tubes. The long tubes did better everywhere else. Both were massive improvements over the stock 2 1/4" outlet log style truck manifolds.

I pulled BBK equal length shorties off my mildly cammed 5.7 Hemi Ram and ran long tubes with the same primary size. I had picked up nearly 3 tenths with the shorties in the 1/8th. I picked up nearly 4 tenths more with the long tubes. Using the same 2.5" to single 3.5" exhaust system and same muffler. I had already deleted the cats prior to removing the OEM manifolds. I hained power everywhere in the powerband and ran nearly 2 mph quicker through the traps.

You can believe what ever you want to, but all research I have seen say the same thing. Shorty headers work better @ bottom end, long tubes are better at mid to high RPMs. How many videos do I need to post that say this, to prove it to you. Not trying to be an ass, but the truth is the truth.
Here you go. go through the utube videos for yourself
https://www.youtube.com/results?search_query=shoty+headers+ve+long+tube

 

[kennythewelder]

I do not! I saw a big header comparison on the same 350 Vortec engine about 10 years ago. Same primary diameter. Same collector diameter. Only difference was short vs long. Same exhaust piping and mufflers were used as well. The shorties had a very narrow rpm band in the 4,500-5,000 rpm range they out performed the long tubes. The long tubes did better everywhere else. Both were massive improvements over the stock 2 1/4" outlet log style truck manifolds.

I pulled BBK equal length shorties off my mildly cammed 5.7 Hemi Ram and ran long tubes with the same primary size. I had picked up nearly 3 tenths with the shorties in the 1/8th. I picked up nearly 4 tenths more with the long tubes. Using the same 2.5" to single 3.5" exhaust system and same muffler. I had already deleted the cats prior to removing the OEM manifolds. I hained power everywhere in the powerband and ran nearly 2 mph quicker through the traps.

One more thing, if you don't like shorty headers, then don't use them. As for me, I have a set, and I like them. I know what they do , and where I saw the improvement in my 97 votrec 5.7L 350.

 

[L31MaxExpress]

I know what headers do as well and have run sets of both. Will say that anything a shorty header can do a long tube can do better with the exception of bolting to the factory exhaust.

I have videos before and after in similar weather conditions. When I installed the long tubes I added cutouts but the difference between open and closed in performance was minimal.

This was BBK equal length shorty headers into 2.5 pipes into a 2.5 to 3.5 merge Y and 3.5" magnaflow. This run was in the very low 9s. Like a 9.08s 1/8.

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Inside run

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This was with Pacesetter 1 3/4" long tubes, 3" to 2.5" cone reducer, same 2.5" to 3.5" merge Y. Cutouts after the cone reducer on both sides. These runs were mid 8.60s in the 1/8 and 13.59 best 1/4. Even the 60ft times were better. So long tubes not making torque is complete and utter BS.

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Inside run

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[L31MaxExpress]

One more thing, if you don't like shorty headers, then don't use them. As for me, I have a set, and I like them. I know what they do , and where I saw the improvement in my 97 votrec 5.7L 350.

I pulled 1 5/8" shorties off my Express van after they started leaking and put Doug Thorley Tri-Ys on it. It was a very noticeable difference across the whole rpm range.

 

[kennythewelder]

Dude, your talking about drag track stuff. I simply stated a simple fact. In a stock. or simi stock for street aps, shorty headers do better at low end torque. Nothing at the drag track, runs from 750 RPMs to 3500 RPM on take off. I have spent enough time at the track. The first thing a drag car does is rev the engine to its limit, and lunch the car at WOT. In this case, yes long tubes with nothing attached is much better. Where short tubes headers do well is from 750 RPS to about 3500, or 4000 RPMs. Everything I posted (all the video) agree with this,,,, EVERYTHING. If your going to pull a boat, trailer, anything, shortys will perform better that long tube headers. If you are going to race, then NO. For this long tube headers are better. Now I am done with this. You can go argue with all of the videos, I have posted.

 

[L31MaxExpress]

Dude, your talking about drag track stuff. I simply stated a simple fact. In a stock. or simi stock for street aps, shorty headers do better at low end torque. Nothing at the drag track, runs from 750 RPMs to 3500 RPM on take off. I have spent enough time at the track. The first thing a drag car does is rev the engine to its limit, and lunch the car at WOT. In this case, yes long tubes with nothing attached is much better. Where short tubes headers do well is from 750 RPS to about 3500, or 4000 RPMs. Everything I posted (all the video) agree with this,,,, EVERYTHING. If your going to pull a boat, trailer, anything, shortys will perform better that long tube headers. If you are going to race, then NO. For this long tube headers are better. Now I am done wtith this. You can go argue with all of the videos, I have posted.

You have to keep in mind that the engine will only accelerate as quickly as the converter stall speed and gearing will allow it to off the line. An improvement in 60' times assuming a dead hook off the line is an improvement in torque. I saw a 60' reduction from a 2.00 to a 1.92 going to long tubes. In the first 60' you are not even close to the redline.

Tri-Ys are better than shorties. I have had both on my Express van that I tow with. Shorties were better than the manifolds. Shorties made the most difference in the 3,500 rpm range but were not as noticeable off-idle or above 4,000 rpm. I spend a fair amount of time in the 4,000-4,500 rpm range when towing uphill.

When I went with the long tubes on the Ram and the Tri-Ys on the Express I noticed better throttle response, quicker acceleration from a stop and fewer downshifts running uphill.

 

[L31MaxExpress]

I just want to say I am not trying to be difficult or anything. Just going off the results I saw from various swaps. My Express van with the tall 3.73 gearing in the axle, 31.5" tall tires, tall 2.48 1st gear of the 85E and the stock converter stalling at 2,400 rpm was rolling in the 30 mph range before the engine ever crested 3,000 rpm. I was playing around with shift points when I added the Tow/Haul button and programming to the 0411. With the Tri-Ys the Express van was actually quicker 0-80 mph shifting at 4,800 than it was with the shorties shifting at 5,300. I was also locking the converter at a lower rpm in 2nd gear with the Tri-Ys. It just made more torque and accelerated better keeping it in the midrange longer. There is a reason Thorley developed and marketed these headers for cutaway chassis buses and box vans. They WORK and fix the cracked manifold problems they have from the heat those applications generate. I saw about 1 mpg improved mileage and experienced about 50% less downshifting on the interstate with the cruise set at 70-85 mph. I wish I had a video clip of the accelaration shifting at 5,300 because it was noticeably quicker than shifting lower. The tri-ys woke the engine up everywhere and require me to add a good amount of fuel to the tune. The PCMs calculated engine torque which is based off airflow, displacement and timing map increased 30+ ft/lbs in all but the 4,000-4,500 rpm range where it still increased ~10 ft/lbs. That same stock converter started brake stalling 2,500 rpm rather than 2,400 too from the increaswd torque output.

Shorties shifting at 5,300.

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Tri-Ys shifting at 4,800

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[Iowan]

 

[Iowan]

All the dyno data I have seen shows that shorty headers help the most up top, but long tubes provide a broader, flatter torque curve. I prefer Tri-y headers. Tri-Ys help more in the mid-top end range but that is where you need it for accelerating uphill, passing or towing.

That also being said the stock 5.7 Vortec Express vans had 3" dual piping from the manifolds to the cats and the cats to the muffler. I never found it lacking in torque, even stock.

I haven’t been able to find TRI-Y headers for the K1500

 

[L31MaxExpress]

This was a less than optimal dyno. 5.7 Vortec with the 395 marine cam and 1.7 rockers. It was floating the valves on the top end and only peaked HP at 4,400 rpm. 2nd gear pull, converter locked through a 4L85E and 9.5" 14-bolt. Hardly the torque curve of a drag racer, lol! The runs were also interesting in other ways. The brief aborted run was a 3rd gear, converter locked pull up to 100 mph. The last run was actually run 4 as there was a partial run not recorded that gave a downshift. The last run was screaming the durmax fan up until the 5,000 rpm range. Found it suprising a locked fan clutch turning a duramax fan with a 25% underdrive only eats about 10 rwhp when the electric fan companies advertise 20 in some cases.

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