1995 K1500 header install

I’ve thought about headers off and on for about 5 years. After 20 years of use one of the OEM manifolds developed a crack so I decided to take the plunge. I don’t care much for the shorty headers that bolt in place of manifolds. For a compromise between fit and function I decided on a set of mid-length headers. I have a well-respected header design program called Pipemax. For a 5.7L engine making 300 hp at 4,800 rpm (my goal) it recommends 1.275” -1.4” I.D. primaries and a 2.5” OD collector. The big name offerings used 1-5/8” diameter 18 gauge tube which is both oversized and a little light for truck use. Some of them also have a poorly shaped 3” diameter collector. I came across L&L Products that manufactures their own line of headers in-house in Texas. They offer a header with 1-1/2” diameter 14 gauge (0.090" wall) primary tubes (1.320” I.D.) a 2-1/2” merge collector ½” thick flanges and a high temp nickel coating inside and out. The flange opening is about the same size and shape as a stock SBC exhaust port unlike many of the big name headers with a huge flange opening to accommodate big aftermarket performance heads.

Bolting the headers on was pretty straight forward. L&L forgot to send the flange gaskets so I used a set of FelPro 1404s I had kicking around. I ended up deleting the alternator/power steering support bracket on the driver’s side for now. I’m looking at a way to modify and reinstall down the road when I do the engine swap. There is no provision for the hot air tube on the passenger side, which I’ll address before it gets cold. The headers arrived with a set of connecting pipes for twin cat vortec engines. I would have used them, but they were only 2” diameter. Instead, I purchased some 2.5” mandrel bends from Summit an O2 sensor bung and a new Walker cat, and a 2-2.5” into 1-3” merge collector from Cone Engineering to build a custom Y-pipe.

I drove over to my dad’s with the open headers and connecting pipes installed. I had disconnected the O2 sensor and despite getting up to operating temp for several minutes the ECM never through a code. It took dad and I about 4 hours to fab up and install the Y-pipe. I’m pretty pleased with how it came out.

With the headers installed the exhaust note is unchanged at idle and low cruising speeds. I don’t notice any header noise in the cab, probably due to the thickness of the tubes. It has a little deeper rumple when I lean into the throttle, which I like. The rest of the system is 3” single with the longest 7” diameter see-through Magnaflow muffler I could find. I’ve only driven around town so far so I can’t say if it makes any more power. Keep in mind right now I’m running a bone stock 165K mile L05.

Very nice! If you don't me asking, what kind of money on the headers themselves?

$600 shipped.

Just got back from a 25 minute loop I like to take when I'm tuning, which includes a flat section of highway where I can run a 0-60 mph pull. I was curious whether the headers would require any changes to the VE tables. Nope. The BLM average were in the 122-128 range; where they've been for the last year. The WOT 0-60 mph run yielded the same 10.0 second time it always has. So my bone stock LO5 shifting at 4,400 rpm sees no benefit at all running a good set of headers and a 2-1/2" Y-pipe as compared to the stock iron manifolds and 2" Y-pipe. Can't say I'm disappointed, or even really surprised. It does sound better. And I'm certain this exhaust system will be much better suited to support the 300 hp engine, once I get around to finishing and installing it.

I too contemplated on a set of headers for my cherokee for a long time. I did end up going ahead and buying some. Mine are full length and I did feel a noticeable difference in power and sound, both for the good. Sorry to hear yours did not make a difference.

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Originally Posted by Roadknee

Just got back from a 25 minute loop I like to take when I'm tuning, which includes a flat section of highway where I can run a 0-60 mph pull. I was curious whether the headers would require any changes to the VE tables. Nope. The BLM average were in the 122-128 range; where they've been for the last year. The WOT 0-60 mph run yielded the same 10.0 second time it always has. So my bone stock LO5 shifting at 4,400 rpm sees no benefit at all running a good set of headers and a 2-1/2" Y-pipe as compared to the stock iron manifolds and 2" Y-pipe. Can't say I'm disappointed, or even really surprised. It does sound better. And I'm certain this exhaust system will be much better suited to support the 300 hp engine, once I get around to finishing and installing it.

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Primaries are too small on your headers to see any real HP gains. There is a reason the aftermarket all use 1 5/8" or 1 3/4" primaries. I had a set of Flowtech 115000 1 1/2 primary, 3" collector headers into dual 2.5" exhaust with a X pipe on my 305 and later 350 in my 83 G20 with TBI swap. Going from manifolds to headers and a good exhaust was VERY noticeable even with the small factory marine cam (200/212 @ .050", .400/.410 on 110 lsa) I had in the 305 at the time. I was putting down about 180 RWHP and 270 RWTQ from the 305. I swapped a stock TBI 350 gm crate engine into the 305s place after overheating it an popping a head gasket. Made 178 RWHP and 262 RWTQ. I did a few extra bolt-ons (TBI spacer with open center, power bowl, 454 TBI, 1.6:1 full roller rockers, and an underdrive pulley) )and got it up to 210 RWHP/310RWTQ. When I got serious with the 350, I swapped to Doug Thorley Tri-ys with 1 5/8" primaries, 2" intermediate pipes and 2.5" collectors using the same 2.5" dual exhaust. Even before the cam swap the header change alone was once again very noticeable. With a production LT4 cam, 1.6:1 rockers and my setup I was cranking out 255 RWHP and 320 RWTQ.

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Originally Posted by Fast355

Primaries are too small on your headers to see any real HP gains.

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This can not be any further from the truth based on the experience of professionals that make their living designing and building custom headers and exhaust systems for winning teams

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Originally Posted by Fast355

There is a reason the aftermarket all use 1 5/8" or 1 3/4" primaries.

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There is a reason and it's because companies are in business to sell product, and the belief of majority consumers that bigger must be better.

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Originally Posted by Roadknee

This can not be any further from the truth based on the experience of professionals that make their living designing and building custom headers and exhaust systems for winning teams

There is a reason and it's because companies are in business to sell product, and the belief of majority consumers that bigger must be better.

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Actually what I wrote is pretty accurate. Plenty of dyno data out there that supports what I posted as well as personal real world experience. The LT1 cammed 1999 Suburban picked up very noticeably with Hooker 1 5/8 primary long tubes with 2.5" collectors into a Hooker 2.25" dual exhaust setup running thunderbolt 5" spun metallic core cats and hooker aerochamber mufflers.

My Titan gained almost 30 RWHP on a Mustang dyno stepping up from the factory manifold cats to catless 1 3/4" 14 gauge T304L mid length headers with 2.5" merge collectors into the 2.25" dual exhaust. It was a monster after headers for a 5,800 lbs 4x4.

The 305 Vortec in the Corvette had a set of stock L82 Ramshorns on it and I put 1 3/4" primary, 2.5" collector headers onto the same dual 2.5" exhaust it had with the ramshorn. Ran 2-3 tenths quicker in the 1/8 with zero other changes.

I was running 0-70 in 8 seconds in nearly 100*F weather in a 5800# truck with a 5.6L engine and 1 3/4" primary headers. It got out of its own way pretty quickly.

http://www.youtube.com/watch?v=lELdtvmah2A


http://i243.photobucket.com/albums/f...ps8j2p9oy1.jpg

http://i243.photobucket.com/albums/f...psywdxhb0s.jpg

I also towed with it, plenty of low-midrange grunt over stock.
http://i243.photobucket.com/albums/f...ps4wyjlw4g.png

The Express has Thorley Tri-ys and gained noticeably as well even shifting at only 4,900-5,000 rpm in Tow/Haul mode.


http://i243.photobucket.com/albums/f...ps5vdojalf.jpg

Doug Thorley even used dual 3" pipes to mate the headers to the factory Express van exhausts. I reduced from 3" to 2.75" to 2.5" at the cats and used a dual in/single out muffler.

http://i243.photobucket.com/albums/f...psahbptb8c.jpg

The van has a huge gearing disadvantage compared to the 5spd in the Titan yet it still pulled down a respectable ~8.xs 0-60 and 11 sec 0-70. For a 6,200 lbs beast with only a 3.73 gear and a 4L80E it is not short on torque by any means. The 4L80Es tall 2.48 1st and 1.48 2nd gear ratios are like having a 3.00 rear gear with a 4L60E in first and a 3.23 in 2nd and the 60 lbs stock 13" torque converter also doesn't help the off the line jump very well either, despite having a dual stator and 2,200 rpm stall speed. When you go WOT from idle it kinda lags, hesitates for a second, then takes off like a proded bull!

http://www.youtube.com/watch?v=-6DZhPN7VHQ

Finally the 99 Burb....0-80 mph in 13 seconds on an uphill onramp in 90*F weather.

http://www.youtube.com/watch?v=LYdyu501Z4Y

Like I said I think I have a little first hand experience at making these engines run pretty strongly.

I also had both 1 1/2" long tubes and 1 5/8" tri-ys on the same engine in my G20, the larger tri-ys blew the smaller headers away from off-idle through redline.

http://i243.photobucket.com/albums/f...m/100_0782.jpg

When I put the healthy TPI enging into the G20 I was glad I had the extra headroom to make more power.

http://i243.photobucket.com/albums/f...album/TPI3.jpg

Im no expert but I've done a ridiculous amount of research in choosing headers for my build. The general consensus on primary size is where you want your power, smaller = low and mid range while larger = more top end. Port alignment and collector size/design are every bit as important as primary size. Just because you saw gains with larger primaries doesn't mean it is because they were larger, its the complete package that makes a difference.

Superchevy has an article on a header test using a smeding 383 and 4 different size headers. The 1 1/2" primary, while intended to just establish a base line for the test, supported well over 400 hp and ended providing the best overall power curve below 5000 rpm. The larger sizes didn't pull ahead until 4500+ and at the sacrifice of low end. Headers by Ed states that there is no point in having a primary size larger than your exhaust valve so if you have a typical svc with 1.5" valves, no need. Unless you're building a high rpm motor, bigger is not better.

If your talking vortec heads, the biggest problem is port alignment. Unlike standard sbc heads, vortec's have a raised port (approx 60% of the port is above the bolt centerline) so smaller primary headers tend to cover the top of the port. Bigger primaries while uncovering the whole port present sealing problems at the bottom of the flange.

I myself went with a set of flowtec 11508 flt headers (less than $150). Basically the same headers in superchevy's test, 1 1/2 primary and 2 1/2 collector. Replaced the wimpy 1/4" flanges with a set of 3/8" cnc cut flanges that I bought on ebay from Hells Gate Hotrods. He sells a set of sbc for $45 and made me a custom set for the vortec port alighnment for less than $100. I went a step further and bought a set of Meg's weld on merge collectors from cone engineering for $125. After finish assembly I sent them to a place called pro kote Indy in Indianapolis and had them professionally cleaned and ceramic coated for $220. Just got them back and they look awesome. For less than $600 I got ceramic coated, perfect fit headers with perfect port alignment and plenty of sealing surface.

Assembling motor now. Let you know how the do when I get it running.

Im no expert but I've done a ridiculous amount of research in choosing headers for my build. The general consensus on primary size is where you want your power, smaller = low and mid range while larger = more top end. Port alignment and collector size/design are every bit as important as primary size. Just because you saw gains with larger primaries doesn't mean it is because they were larger, its the complete package that makes a difference.

Superchevy has an article on a header test using a smeding 383 and 4 different size headers. The 1 1/2" primary, while intended to just establish a base line for the test, supported well over 400 hp and ended providing the best overall power curve below 5000 rpm. The larger sizes didn't pull ahead until 4500+ and at the sacrifice of low end. Headers by Ed states that there is no point in having a primary size larger than your exhaust valve so if you have a typical svc with 1.5" valves, no need. Unless you're building a high rpm motor, bigger is not better.

If your talking vortec heads, the biggest problem is port alignment. Unlike standard sbc heads, vortec's have a raised port (approx 60% of the port is above the bolt centerline) so smaller primary headers tend to cover the top of the port. Bigger primaries while uncovering the whole port present sealing problems at the bottom of the flange.

I myself went with a set of flowtec 11508 flt headers (less than $150). Basically the same headers in superchevy's test, 1 1/2 primary and 2 1/2 collector. Replaced the wimpy 1/4" flanges with a set of 3/8" cnc cut flanges that I bought on ebay from Hells Gate Hotrods. He sells a set of sbc for $45 and made me a custom set for the vortec port alighnment for less than $100. I went a step further and bought a set of Meg's weld on merge collectors from cone engineering for $125. After finish assembly I sent them to a place called pro kote Indy in Indianapolis and had them professionally cleaned and ceramic coated for $220. Just got them back and they look awesome. For less than $600 I got ceramic coated, perfect fit headers with perfect port alignment and plenty of sealing surface.

Assembling motor now. Let you know how the do when I get it running.

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Originally Posted by old truck guy

Assembling motor now. Let you know how the do when I get it running.

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The cam in your signature is one of the ones I considered using. It actually came down to the that one and the one I am using now which has much less lift. I'd like to hear how it works for you.

BLG

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Originally Posted by BLG355

The cam in your signature is one of the ones I considered using. It actually came down to the that one and the one I am using now witch has much less lift. I'd like to hear how it works for you.

BLG

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Yeah I was concerned about lift too. Spring upgrade in my vortec's is good to about .550 which is right where the advertised lift for my cam is but it's spec'd with 1.6 rockers. I went with 1.52 which brings my total lift down to about .522. Your, s sounds like a nice build. A bit more than mine. Is that isky enough cam?

I thought about going with a larger cam, but I do planning on doing some towing and I wanted a big increase over stock without any drivability issues. To keep things simple to pass the PA emissions test, I decided to go with the Edelbrock TBI intake so the EGR was physically bolted in the proper place. So that lead me to look at the Dart S/S heads, which stop increasing flow rate at .500" lift. And the dart heads have a very nice combustion chamber, plus it is 72cc. I wanted to keep a good quench distance of .039 and with flat tops with only 2 valve reliefs, I am right at 8.0 dynamic compression with this cam. So, for this motor, this cam has incredible torque, plus just enough to pull 5500rpm shift points. I upgraded to the 454 throttle body because I was down to 88kpa at 5200rpm, now the motor is over 95kpa at 5500+ rpm(not that I need it there). If I was going with different heads I probably would have went for the comp cam, but I do love Isky grinds. I use them in race motors with excellent results.

BLG

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Originally Posted by Fast355

Like I said I think I have a little first hand experience at making these engines run pretty strongly.

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I don't think you'll find anyone who will disagree with that. I've personally been very impressed with your results for about a decade now. I simply don't agree with your opinion that 1-1/2" headers are holding back my stock LO5. FWIW, I don't think it would gain or lose anything measurable with a decent set of 1-5/8" headers either.

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Originally Posted by Roadknee

I don't think you'll find anyone who will disagree with that. I've personally been very impressed with your results for about a decade now. I simply don't agree with your opinion that 1-1/2" headers are holding back my stock LO5. FWIW, I don't think it would gain or lose anything measurable with a decent set of 1-5/8" headers either.

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Its possible your stock cam has a choke hold on the engine and it just can't move any more air through the valves but honestly I have never not seen gains with headers.

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Originally Posted by BLG355

The cam in your signature is one of the ones I considered using. It actually came down to the that one and the one I am using now witch has much less lift. I'd like to hear how it works for you.

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The Isky with 1.6 rockers and the comp with 1.52 rockers will have pretty similar valve lift curves. The Isky comes off the seat a little quicker, but the Comp will have a few more degrees duration above 0.200" tappet lift. The Comp with a slightly wider LSA and more exhaust duration might pull slightly harder above 5,000 rpm. I think their characteristics will be so close, it would not be worth the effort or expense to change from one to the other.

If a person were to spend about an hour swapping relevant parameters from BLG's bin to Old Truck Guy's, I think it would run and drive pretty good on the first try.

I worked on a 97 C1500 5.7 truck Thursday evening. Installed BBK shorty headers into 2.5" Jegs offroad head pipes and matching catback exhaust. Then swapped on a set of Jegs 1.6:1 full roller rockers. A Volant cold air intake and March underdrive pulleys. The truck already had a built 4L60E and 3.90 gears with a Grizzly locker. Runs around on heavy 20" wheels. Truck also already has a larger 454 radiator and 34" Tahoe Efans. I had previously swapped an 0411 into this truck and HP Tuned it. Was seeing about 200 gms/sec airflow. Now seeing 260 gms/sec and the truck is a completely different truck power wise. Next up is a hotter cam.

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Originally Posted by Roadknee

If a person were to spend about an hour swapping relevant parameters from BLG's bin to Old Truck Guy's, I think it would run and drive pretty good on the first try.

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Putting the heads on as we speak. Hopefully have the motor back in by the end of the weekend. Dave W has created my start up bin already and is sending it to me. Hopefully its close on start-up :-). Be interesting to compare it to BLG's.

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Originally Posted by Fast355

Its possible your stock cam has a choke hold on the engine and it just can't move any more air through the valves but honestly I have never not seen gains with headers.

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I might have found an explanation. Since I began tuning this engine a year and a half ago I've fought knock retard. Looking back at my latest log it was pulling timing at WOT and the max the engine ever saw was about 13 degrees. This is with 92 octane fuel. I decided to take a risk and disable knock retard. I kept the spark table pretty conservative with about 5 degrees at 400 rpm and 20 degrees at 4,000 rpm WOT. Went for another run and my 0-60 times increased... due to violent wheelspin off the line. So I compared 40-60 mph times and the increased timing dropped a full 0.5 second. Yes, knock counts were climbing the whole time but at this point I don't care. If it blows up I'll need to get off my behind and put the new engine together.

Earlier in the week I took a trip to the west side of the state over two mountain passes and honestly the truck has never run this good since I bought it in 1999. More power everywhere and ultra smooth. I had the laptop connected for the trip over and even driving conservatively it picked up 11,000 knock counts in the first 150 miles. They really start to climb at about 2/3 to 3/4 throttle and 2,500 rpm, but the engine is only seeing 20-22 degrees of timing. As I stated earlier, at this point I'm done worrying about it.

roadknee, I got a 4.3 v6 that is worn out and it developes a lot of knock counts and I hate it.i put a set of fine wire bosch plugs in it and it help the knock counts.stock engine almost stock timming table the ac delco plugs would look blue as if thay were glowing at 70mph cruise on the ground side of the plug. the old 288 don't retard timming with the bin I have. it might be the bosch plugs are a little shorter than the ac plugs, it didn't cure my knocks but it helped using them fine wired plugs.

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Originally Posted by Roadknee

I might have found an explanation. Since I began tuning this engine a year and a half ago I've fought knock retard. Looking back at my latest log it was pulling timing at WOT and the max the engine ever saw was about 13 degrees. This is with 92 octane fuel. I decided to take a risk and disable knock retard. I kept the spark table pretty conservative with about 5 degrees at 400 rpm and 20 degrees at 4,000 rpm WOT. Went for another run and my 0-60 times increased... due to violent wheelspin off the line. So I compared 40-60 mph times and the increased timing dropped a full 0.5 second. Yes, knock counts were climbing the whole time but at this point I don't care. If it blows up I'll need to get off my behind and put the new engine together.

Earlier in the week I took a trip to the west side of the state over two mountain passes and honestly the truck has never run this good since I bought it in 1999. More power everywhere and ultra smooth. I had the laptop connected for the trip over and even driving conservatively it picked up 11,000 knock counts in the first 150 miles. They really start to climb at about 2/3 to 3/4 throttle and 2,500 rpm, but the engine is only seeing 20-22 degrees of timing. As I stated earlier, at this point I'm done worrying about it.

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go with a hotter plug. i had a similar problem my knock counts would be maxed out within a 30 minute drive. went from a r44lts to a r42lts plug (ac delco) and knock counts dropped to the teens. i like ac delco plugs only. apparently proper torque on the knock sensor is crucial as well. I think it's 13 ft.lbs. you can also add a brass elbow (90 or 45 degree) to "lessen" or TUNE the knock signal.