First off let me start with I'm looking at all options. I have a 2002 gmc.sierra 1500 HD crew cab 4wd with the 6.0l I believe lq4 engine. Truck has 225k miles on it and is still a work horse for sure. I notice the engine is running a little noiser as time goes on. I WORK this truck hard everyday.

With that said I want to rebuild something and have it ready to drop in when my current engine goes.

I prefer to be able to use factory Harness and computer (will end up with custom tune later). Keep factory trans for now and start using it everyday.

No the fun part. What block do you recommend? Do I put ls parts into a lq4 or switch to something different?

I don't want to go turbo I want to keep it NA. I also would like to make around 425 to 450 hp.

Any help is greatly appreciated. My truck is really clean for its age and I really want to keep working it.

 

Find a LQ9 for the better of the two 6.0's, has a little more power to begin with and better bottom end in the later years.

A camshaft upgrade and some long tube headers would wake the engine up and give you plenty of power. 400+ crank horsepower should be within reach on a good solid tune.

 

The LQ4 and LQ9 use the same block. If your going to rebuild it any way, don't spend the extra coin on the LQ9. Use it toward the rebuild cost.
You would be literally throwing away money If you purchased an LQ9 and then proceeded to have it rebuilt.

You can purchase the same flat top pistons that are used in the LQ9 and the floating rods and still have money left over.

A mild cam and tune will easily make the power you seek.

BTW, these engines are all based on the LS platforum. Hope That Helps!!!

 

I wouldn't spend the money on getting another engine while you already have the perfect platform for your needs. Just get your money together to have someone skilled to yank that motor, freshen it up, throw in a baby cam, long tubes, and a good tune. Your goal doesn't need any strong hardware in my opinion.

For the love of God please please remember that you have a fat truck and you don't need much cam to keep your power useful.

 

The guy is looking to keep his truck running while another engine is built by the looks so the whole rebuild existing won't really work.... You could find another low mileage 6 liter of one form or mod it or do a rebuild on any old 6 liter core...... Totally your choice. Compression bump is a nice idea with an LQ4 so just adding 243/799 heads to one gets you over 10:1..... around 10.3-10.4 depending on gasket used and how much the factory piston protrudes from the block. Doing that and a mild cam with a set of headers would be leaps and bounds over what you have now.

 

Buy a crate engine and be done with it.

 

I had one from ATK before my mishap with the Whipple. I'll vouch for it. It was strong as **** and never gave me any issues.

The cam they use is similar to BTR's stage 3 truck cam. Off-idle torque is great, more so if you have a stall. Smooth idle, no chop, no sound of it being cammed.

 

Find a good used lq4 or 1q9 put that in the truck,then do what he said with your original engine. Limit your down time and achieve your build.