motoman501

Hello everyone. I got an 03 chevy 1500hd lq4. I'm trying to make around 450 hp at the wheels. I would like to build a super reliable top end. Gonna keep her under 6500 rpm I'm swapping everything from the cam up to intake manifold.
I know I want the truck norris btr cam
Lifters still up in the air
Pushrods still up in the air
Trunion upgrade
Comp 918 springs
Head swap from 817s to 706 or similar with port polish
Injectors then a tune
Anything I'm missing or suggestions as I am fairly new to the ls tech thx

Jake Wade

Anything I'm missing?


Boost. You would need roughly 525 crank HP to achieve 450 wheel. I don’t think you will achieve that with the CN camshaft N/A.

strutaeng

The 1500HDs (they are really closer to 2500HDs than "1500"s of that generation, in my opinion) came with 3.73 gears standard, right? Have you thought about going with 4.10s to get your RPM up a little higher? Are you running stock tires?

LS1Formulation

iTrader: (13)

450 at the wheels with 20% driveline loss ( conservatively, given your drivetrain in that truck ) is 540 at the crank. You won't get there with stock ported heads, I can tell you that. A set of AFR 230s will get you there, however. If you look at Richard Holdener's LS intake test video, he had a 370 cube LQ4 with those heads, a 231/247 cam with 113 LSA and .624/.617 lift, and running a TBSS intake, it made 562 HP. Stock truck intake was closer to 540. With accessory drive losses and drivetrain losses, that 562 HP will probably land slightly under 450 at the wheels, I'm guessing. I don't think the Truck Norris cam will support that kind of power, though. It's a good cam, for sure, but you gotta wind an engine out to get great HP figures when you're limited on displacement ( and therefore, torque ).

Fast355

4L80E and 10.5" 14 bolt will eat nearly 25% of your horsepower. You can save a few HP using electric fans, but I would keep the mechanical if the goal is towing. Remember torque is going to do more for you towing than HP. Personally I would drop an 8.1L into it with a mild cam upgrade. I have 2 of them and they will run circles around a NA 6.0L while towing. My 8.1L only makes ~450 hp at the crank, but does that at 5,000 rpm and makes 550 tq @ 3,500 with nearly 500 practically off-idle. The one in my 99 Tahoe is a stock engine with the HO marine cam, long tubes and a 4" air inlet with a LS3 4" MAF.

8.1L can mostly re-use the LS harness, throttle body and PCM. Program the PCM with a 2003 8.1L Suburban or Avalanche tune. I have put an 8.1L into a 2005 Express 3500 cut-away as well. It is the engine GM should have put into those. The only modification required to physically get the the 8.1L in was the bracket on the frame on IIRC the passenger side. The one for the 8.1L is shorter and I had to get one from an 8.1L truck. I snagged the fan shroud and air intake ducting from the same truck. Look at what LT has done with his junkyard 8.1.

motoman501

Thank you all for your input. So 450 hp is my ideal goal to hit. If I get to the low 400s I wouldnt be disappointed. I have $2500 budget and $500 for a tune the truck does have 3.73 gears and yes the 4.10s would be a future upgrade ive already considered. Reason I'm starting with the top is I believe I have a lifter ticking and want to fix that while upgrading everything it takes to get there. I was thinking of doing a holly low ram intake with a custom aluminum adaptor plate and a svt 5.8 but I'd run into problems smoging and have to hot smog.

Kawboom

DO NOT PUT A HOLLEY LOW RAM ON THAT ENGINE!!!

Get a Trailblazer SS intake.

motoman501

Do you have any reason why not to put a holly low ram?

Kawboom

Compared to the stock manifold the low ram is straight up losing 40 ft-lb of torque everywhere until you get to the very top end of 6000+ rpm, and then it only ties the stock TBSS manifold on a small engine in power production. The Low Ram is meant for a car engine with a fair amount of cam and a very low hood or a turbo where they don't care about manifold torque because you can just turn the wastegate up.

You can get a reproduction TBSS manifold for like $190.

LS1Formulation

iTrader: (13)

Absolutely second that idea. Any short runner intake is absolutely useless on a vehicle used for towing. TBSS is a great upgrade over the truck intake, to the tune of 10-15 HP and a similar amount of torque through the WHOLE rev range.

Fast355

One thing I just noticed; the OP is in California. Given that they cannot run any form of non-stock tuning and get through inspection, everything has to have a CARB EO# and more. He really just needs to do a stock rebuild and leave it alone. At one point there were a couple of manufacturers that had CARB legal superchargers or blowers for these trucks.

Ls7colorado

iTrader: (3)

You might get 300-350 RWHP with that setup. I am runing the TN cam and 243/799 heads on my 2500 with long tubes and it picked up quite a bit of power but no way its ever gonna get close to 400RWHP without boost or a possibly a stroker build with nice heads.

Rancherlee

Since you used the word TOWING in your title there are 2 ways to 450rwhp, either boost on the bone stock engine or rebuild to a 408 stroker. It really depends on what your "towing" is also. If it's a 16ft boat to a local lake or a few ATV's then you can go a bit more wild with some compression and the Truck Norris cam (maybe ~375rwhp). An enclosed car trailer for hundreds of miles, you would be best with a VERY mild cam (stage 1 truck/torque cam) and leaving the compression alone (~325rwhp, still a healthy gain over stock). You can't really apply "car builds/youtube dyno vids" to tow vehicles, with a truck you might be pulling a grade for minutes @ torque peak which puts a lot more stress/heat on components then a 10 second dyno pull / drag strip pass hence Lower compression. I'm only expecting the 9.7:1 compression 408 in Chevelle to make ~450rwhp with a 4L80e/9" and that has a 222/233 cam, TSP ported 317 heads, TBSS intake, and 1 3/4 longtubes.

Fast355

I tow with an 11:1 SBC 383 without issue and its not a light or aerodynamic setup. That being said in California without being able to tune the PCM it would not be possible.