LQ4 truck build
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LQ4 truck build I am looking to get some more power and torque out of my 2003 Chevy 2500hd. This truck does some towing but mostly a daily driver.
Questions:
Will this set up run on regular 87 when not towing? When I am towing plan to use premium.
Will hd2 kit extend the life of the trans?
parts list:
gm 799/243 heads
truck Norris or chopacabra cam
valve spring upgrade
long tube headers
No cats
transmission:
trans go hd2
larger cooler
deep pan
Questions:
Will this set up run on regular 87 when not towing? When I am towing plan to use premium.
Will hd2 kit extend the life of the trans?
parts list:
gm 799/243 heads
truck Norris or chopacabra cam
valve spring upgrade
long tube headers
No cats
transmission:
trans go hd2
larger cooler
deep pan
Last edited by RCDls’s; Jan 7, 2025 at 05:23 AM.
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Posts: 418
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From: Franconia, PA
Consider this cam: summit 8728. Big torkinator
https://www.summitracing.com/parts/s...824yHuK4x6YzHB
https://www.summitracing.com/parts/s...824yHuK4x6YzHB
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I am looking to get some more power and torque out of my 2003 Chevy 2500hd. This truck does some towing but mostly a daily driver.
Questions:
Will this set up run on regular 83 when not towing? When I am towing plan to use premium.
Will hd2 kit extend the life of the trans?
parts list:
gm 799/243 heads
truck Norris or chopacabra cam
valve spring upgrade
long tube headers
No cats
transmission:
trans go hd2
larger cooler
deep pan
Questions:
Will this set up run on regular 83 when not towing? When I am towing plan to use premium.
Will hd2 kit extend the life of the trans?
parts list:
gm 799/243 heads
truck Norris or chopacabra cam
valve spring upgrade
long tube headers
No cats
transmission:
trans go hd2
larger cooler
deep pan
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Joined: May 2023
Posts: 418
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From: Franconia, PA
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How many miles on the engine and trans? I rebuilt my 4L80E and the internal bushings where shot at 300k miles and the large clearances were starting to make transmission noise. My piston rings started having sealing problems past 330k as well. Something to think about if you have close to 300k miles on a 20+ year old truck.
Back when my 01 1500HD was closer to stock, I added a small wide LSA (~115deg) cam to keep cylinder pressure high and it gained a mid RPM, audible detonation in the upper 2K to 4K rpm range with the stock 317 heads. Picked up noticeable power in that range. I like your narrower LSA to try and stay on 87 octane, but I wouldn't use the smaller chamber 799 heads as that will raise your compression and may push you out of 87 octane.
Back when my 01 1500HD was closer to stock, I added a small wide LSA (~115deg) cam to keep cylinder pressure high and it gained a mid RPM, audible detonation in the upper 2K to 4K rpm range with the stock 317 heads. Picked up noticeable power in that range. I like your narrower LSA to try and stay on 87 octane, but I wouldn't use the smaller chamber 799 heads as that will raise your compression and may push you out of 87 octane.
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How many miles on the engine and trans? I rebuilt my 4L80E and the internal bushings where shot at 300k miles and the large clearances were starting to make transmission noise. My piston rings started having sealing problems past 330k as well. Something to think about if you have close to 300k miles on a 20+ year old truck.
Back when my 01 1500HD was closer to stock, I added a small wide LSA (~115deg) cam to keep cylinder pressure high and it gained a mid RPM, audible detonation in the upper 2K to 4K rpm range with the stock 317 heads. Picked up noticeable power in that range. I like your narrower LSA to try and stay on 87 octane, but I wouldn't use the smaller chamber 799 heads as that will raise your compression and may push you out of 87 octane.
Back when my 01 1500HD was closer to stock, I added a small wide LSA (~115deg) cam to keep cylinder pressure high and it gained a mid RPM, audible detonation in the upper 2K to 4K rpm range with the stock 317 heads. Picked up noticeable power in that range. I like your narrower LSA to try and stay on 87 octane, but I wouldn't use the smaller chamber 799 heads as that will raise your compression and may push you out of 87 octane.
I would absolutely to the trans stuff. I went with a cooler twice the size as stock rather than one of the huge ones and are very happy towing. Absolutely do cam and supporting things like springs. I would keep the stock heads. The headers are up to you. If you are messing with the exhaust anyway, then why not, but they will take away some very low end torque for more mid and high rpm power. The stock manifolds flow a lot. Wrap the headers and spray them with exhaust paint to keep the under hood heat down.
The two mods that made the most difference when I was close to stock was cam and tune.
The two mods that made the most difference when I was close to stock was cam and tune.
I have the same truck, lq4 4l80, swapped 799 heads on, truck norris cam, long tubes, and ls6 valvesprings.
At first I was just running 93 octane but I actually tried 87 and even with my 93 tune in it I only had detonation below 2200 or so rpm at HIGH load.
I pulled some timing and made it safe, now even towing I get no detonation on 87.
If I want a little more power I switch to 93 and load that tune back in.
At first I was just running 93 octane but I actually tried 87 and even with my 93 tune in it I only had detonation below 2200 or so rpm at HIGH load.
I pulled some timing and made it safe, now even towing I get no detonation on 87.
If I want a little more power I switch to 93 and load that tune back in.
Last edited by Ls7colorado; Jan 11, 2025 at 08:05 AM.
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OP,
We really like the direction you’re heading with the cams and 799/243 heads for this setup and your goals. As @Abs mentioned, take a look at our SUM-8728R1 "Big Torkinator" cam. It’s a strong contender with specs at .600/.585, 212/218, 110+3, and -5° of overlap. It’s in the same range as the other cams you’re considering but comes at a better price point. This cam will give you a steady lope while remaining easy to tune and manageable as a daily driver. It’s designed to make great torque from 2,000 RPM all the way up to 6,500+ RPM with .600" lift beehives.
The 243 heads will help bump your compression ratio from 9.4:1 to around 10:1 using a .051" head gasket. This would be fine for use with 87 for daily use and maybe even for towing with the right tuning. Since you’re planning to run 93 octane for towing, you might want to consider .040" head gaskets for an additional .2–.3 increase in compression. This also reduces quench distance, promoting a more efficient combustion cycle and lowering the chance of knock.
Your long tubes and free-flowing exhaust will further enhance the performance of any of the cams mentioned, so you’re already set up for success. Just remember, a proper custom tune is key—it will optimize your setup, ensuring you get the most out of your combo while keeping everything running smoothly.
Let us know if you have any questions or if there’s anything else we can assist with. We’re here to help!
We really like the direction you’re heading with the cams and 799/243 heads for this setup and your goals. As @Abs mentioned, take a look at our SUM-8728R1 "Big Torkinator" cam. It’s a strong contender with specs at .600/.585, 212/218, 110+3, and -5° of overlap. It’s in the same range as the other cams you’re considering but comes at a better price point. This cam will give you a steady lope while remaining easy to tune and manageable as a daily driver. It’s designed to make great torque from 2,000 RPM all the way up to 6,500+ RPM with .600" lift beehives.
The 243 heads will help bump your compression ratio from 9.4:1 to around 10:1 using a .051" head gasket. This would be fine for use with 87 for daily use and maybe even for towing with the right tuning. Since you’re planning to run 93 octane for towing, you might want to consider .040" head gaskets for an additional .2–.3 increase in compression. This also reduces quench distance, promoting a more efficient combustion cycle and lowering the chance of knock.
Your long tubes and free-flowing exhaust will further enhance the performance of any of the cams mentioned, so you’re already set up for success. Just remember, a proper custom tune is key—it will optimize your setup, ensuring you get the most out of your combo while keeping everything running smoothly.
Let us know if you have any questions or if there’s anything else we can assist with. We’re here to help!
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199-BrawlerLS6 Brawler LS6 Style CNC Ported Cylinder Heads w/ TSP .660" Spring Kit and Titanium Retainers
These are another option:
CNC Ported 243 Heads & 799 Heads | LS1/LS6 CNC Ported Heads – Allied Motor Parts
These are non ported heads from allied:
Chevy LS1/LS6 Remanufactured Cylinder Head Pair, Year:97-04 – Allied Motor Parts
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From: Franconia, PA
199-SSPRC220AsCast PRC 15-Degree 220cc As-Cast Cathedral Heads
I had dynatech on my 2002 silverado, and they are still in great shape all these years later. My Dad has that old truck and it has over 340,000 miles on it. Too bad it looks like they are no longer available.