So the project is a 2002 GMC Sierra, with a 4.3L V6 and automatic transmission. It's a 2x4 single cab, short step side bed. Of the trucks, it's on the lighter end of the scale.

We would like to build an aluminum LS1 for the truck. I did search and found a few threads with good information but thought I might ask for suggestions based on this specific project.

To preface, we're not trying to build the engine for max HP. Honestly we want a little more bias towards low RPM torque for cruising and perhaps pulling. I guess you could say we want to build a truck engine. LOL.

We've targeted the F-body LS1 for the aluminum block, and we'll hopefully find a complete donor with ECU and harness.

Once we have the engine, we'll rebuild. Machine shop will do the specialized work and we'll assemble using new and old parts.

My questions:

Any particular LS1 that will be better for a swap into the 2002 truck?

Specifically what induction parts should we change to accommodate the bias towards higher torque, or would stock heads and intake serve that purpose well?

Are there kits available for the common bore size needed when boring a used aluminum block with the iron sleeves?

Engine mount kit?

Exhaust manifold kit?

I assume I would just want the ECU from the LS1 donor car, but what systems from the truck can be retained and what systems from the donor car will we need?

Anything I left out, shout it out. This is all conceptual at this point. We have the truck and in our minds we want an aluminum LS1 built for low end grunt.

Thanks for the help guys.

 

Stay away from 97-98 LS1. The cylinder liners are thin and cannot accept a real overbore.

I advise you to strongly consider just picking up an iron 6.0. You will spend less for more displacement and already have an engine/cam/intake combo that is biased toward low-end torque but also make tons more power than what you have now. The weight penalty for the iron block is only about 100lbs over the LS1 and probably less when compared to the 4.3. And forget the machine shop if you can; find a clean 100-150K mile example and run it another 100K miles. With the 6.0 you also get a 4" bore which allows you to eventually run LS3/L92 heads if you want and make big power cheaply.

My $0.02.

 

^^^^^ ALL of this^^^^^^^

 

I was actually thinking 2000 - 2002.

We've discussed the 6.0L but we want to still with the aluminum LS1. Let's just move forward under that assumption. The rest of the questions can be answered for pretty much any of the V8 swaps to replace the V6, correct?

 

Ok two more paths/options for sanity if you are stuck on Al block. LS2 gets you Al block and all of the other benefits. They are coming down in price. Or start with a low-dollar 4.8 truck. Won't have to change much at all; really just find a LS1 long block and swap it under the truck stuff.

From your earlier response, I'll assume you aren't going to bite on any of that.

Really this is pretty simple. I'm not steering you away from your original plan because there is any real brain work there; it's just that the other options are going to be cheaper and faster with same or better results.

Unless I am missing something about the V6 trucks(haven't had a full size that wasn't V8; just an S10 with 4.3 log ago), this is a straightforward parts--gathering mission. All the things you asked about? Get those from a gen III truck. Run the (V8) truck harness so you can plug it into your truck. Same for exhaust and mounts.

I think this cam would do nicely for what you are aiming for and work well with the truck intake:

http://store.cammotion.com/53-l-325ci-95-compression-2

Speaking of truck intake, the Gen III truck intakes flow pretty well. The Gen IV/NNBS/TBSS intake is a little better and does offer a larger throttle body opening, but with your goal being truck torque primarily, it's probably a waste. The Gen-III truck intake can often be had as cheap as free and will run well. It has been shown to flow better than a stock LS1 intake for all purposes and all ranges; folks just don't run it either because it won't fit under a car hood or they think it is "ugly."

PS-- even Rockauto sells overbore pistons/rings for LS1 and pretty cheaply. If you want higher-end stuff, the typical vendors have had that stuff for over a decade. You just don't see the LS1 stuff "in your face" because a lot of folks have moved on to 4" and larger bore or are mega-boosting 4.8/5.3.

 

Thank you so much for taking the time to put all of that out there. You touched on a lot of the things I was curious about and using that on top of a few of the things I found during the search, we have a good plan put together.

We'll source a 2000-2002 F-body LS. Likely a stock rebuild minus overbore components, and a 'truck' cam and intake.

The rest, as you mentioned, is basically a parts search from V8 trucks.

I found a good place to send the ECU for a proper optimization using the truck's VIN and cam specs.

As we formulate a solid game plan, I'll post for everyone's thoughts.

 

Find a Trail Blazer SS 6.0. aluminum block, Great intake, 400 plus Hp, 243/799 heads . I think I paid 3500 bucks for mine with all the components including the gas pedal.