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Discussion Starter · #1 ·
So I'm new to the group as my daily 2001 GMC with a LM7 has gone out with 295,000 miles on it. I'm looking to start adding some horsepower to it while I have it tore apart for the rebuild. I'm looking for recommendations for parts I should look into. Not looking for crazy horsepower number just more than stock and enough to still be able to tow if I need to.
 

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Check out Texas Speed performance if you’re tearing into the engine. Cam swap and beehive springs, maybe new rockers… they also have some big intake manifolds too if hood clearance isn’t a concern 😂. biggest difference will be a custom tune though. Find somebody using EFI Live. Have em advance timing, run premium, take out about 80% of torque management and change shift points.
 

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Discussion Starter · #3 ·
Check out Texas Speed performance if you’re tearing into the engine. Cam swap and beehive springs, maybe new rockers… they also have some big intake manifolds too if hood clearance isn’t a concern 😂. biggest difference will be a custom tune though. Find somebody using EFI Live. Have em advance timing, run premium, take out about 80% of torque management and change shift points.
With taking out the torque management will that make towing more difficult? I'm still wanting to be able to tow with this truck as it is my only tow vehicle and i have a camper and boat. I was thinking more on the lines of new pistons, cam, ported heads, tune and headers. Not sure if any of that is even worth it or if I would have to add more with certain parts.
 

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No, taking it out will not increase torque.

However, taking it out will allow the torque to be available over a wider range of functions.

For example, taking off from a stop applying gas slowly will allow max torque to be applied to the rear wheels; however, take off with wide open throttle, the computer will dial back the spark and fuel, reducing the torque. Two reasons, max torque quickly applied creates emissions and fuel consumption, it also causes parts to break.
 

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That’s correct. Taking out TM increases Response (not actually an increase in torque) and helps with towing. Why new pistons? Are any burnt? Sure you can do ported heads but by the time you pay to ship them off and pay for labor, you might as well just buy new performance heads.

Cam is easy as long as you don’t go too radical and need a new stall converter, but it won’t be a huge gain by itself. Cams target a specific RPM power band. A good towing cam comes in from 1500 rpm to about 3500 rpm for max torque. After that, a towing cam will start falling off.

Headers, in my experience, only long tubes are worth it. They are expensive, require lots of rerouting and you need to tune out your downstream O2s or deal with CEL staying on. And they are a pain on a 4x4.

again, a tune is your best bet and will make the biggest difference. You’ll need one anyway if you do some of the things on your list.
 

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Discussion Starter · #8 ·
That’s correct. Taking out TM increases Response (not actually an increase in torque) and helps with towing. Why new pistons? Are any burnt? Sure you can do ported heads but by the time you pay to ship them off and pay for labor, you might as well just buy new performance heads.

Cam is easy as long as you don’t go too radical and need a new stall converter, but it won’t be a huge gain by itself. Cams target a specific RPM power band. A good towing cam comes in from 1500 rpm to about 3500 rpm for max torque. After that, they start falling off.

Headers, in my experience, only long tubes are worth it. They are expensive, require lots of rerouting and you need to tune out your downstream O2s or deal with CEL staying on. And they are a pain on a 4x4.

again, a tune is your best bet and will make the biggest difference. You’ll need one anyway if you do some of the things on your list.
With talking to an engine builder buddy of mine he had mentioned that aftermarket pistons provide more compression, I am also planning on buying performance ported heads. Have been told most standard ported heads are no good so performance ported are the way to go for performance gains. Headers for more airflow than stock but will be going for shorty's as I don't want to have to do a bunch of fabrication when i already have straight pipe exhaust. And finally I've been told tune on its own wont make any noticeable gains as truck are mostly tuned pretty high compared to most cars with similar motors.
 

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Discussion Starter · #9 ·
No, taking it out will not increase torque.

However, taking it out will allow the torque to be available over a wider range of functions.

For example, taking off from a stop applying gas slowly will allow max torque to be applied to the rear wheels; however, take off with wide open throttle, the computer will dial back the spark and fuel, reducing the torque. Two reasons, max torque quickly applied creates emissions and fuel consumption, it also causes parts to break.
So I should leave it as is if I want to tow with the truck?
 

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With talking to an engine builder buddy of mine he had mentioned that aftermarket pistons provide more compression, I am also planning on buying performance ported heads. Have been told most standard ported heads are no good so performance ported are the way to go for performance gains. Headers for more airflow than stock but will be going for shorty's as I don't want to have to do a bunch of fabrication when i already have straight pipe exhaust. And finally I've been told tune on its own wont make any noticeable gains as truck are mostly tuned pretty high compared to most cars with similar motors.
Shorties won’t do much for you. And the tune comment is bad advice. These trucks are highly de-tuned from the factory so you don’t break u-joints and rip rear ends and cook the mediocre 4l60e transmission these come with. A tune will be the biggest improvement you see. Voice of experience here.
 

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Discussion Starter · #11 ·
Shorties won’t do much for you. And the tune comment is bad advice. These trucks are highly de-tuned from the factory so you don’t break u-joints and rip rear ends and cook the mediocre 4l60e transmission these come with. A tune will be the biggest improvement you see. Voice of experience here.
I'll do more research on the tune for sure but as far as headers I'm trying to use as much stock location and parts as somewhat possible. So keeping the straight pipe i already have and the factory y-pipe is my best bet for that.
 

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Word of advice, Spend the money for FelPro gaskets and a good set of ceramic boot spark wires unless you want to keep changing burnt wires with the headers and looking for exhaust leaks.
 

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YOU TRUCK HAS 300,000 MILES .....you are towing 4000-8000 pds ...
the factory headers working change the aftermarket headers,, but you have to change the software.. change the injectors to more gasoline and remove the cat converters .. use a muffler with small exhaust restrictions ..change the drive train diffs to 3.73/4.11.....transmission changes the dexron III to the dexron VI / 6 .. probably the truck could have the tow pkg .. if not,,, install the transmission fluid cooler..
change the air filter to open air .
 
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