In the spirit of the new forum I have LS swap questions.

[33shooter]

I'm building a 70' C10 long bed with a LS swap in mind. I plan on using a 4l80e trans and was wondering which motor and gear combo I should look for. I'm hoping to get around 350hp from the motor to the wheels, so I'll probably put a mild cam in and have it tuned. What gear would allow me to get around 20mpg on the hwy with that transmission? Which motor should I go with? 6.0 or 5.3?

I was thinking 3:40 gears and a LY6. Thoughts?

[85burb]

With a 6.0 it should be easy to reach or exceed the hp goal. I am not sure about the mpg one. I have a friend with a 03 2500 with a 6.0 and he gets 14 or so on hiway that is in a 4 door with 4.10 gears. Your truck is much lighter and will have better gears so should be close to your mpg goal. Thats just my thoughts on it.

[glock35ipsc]

Just FYI, my 5.3/4l60E is making 266hp at the tires, which is about 335 at the crank.

If you go with a 5.3, a 4L60E will be plenty of trans. Anything bigger, and I would probably go with a 4L80E. Although, I had a supercharged 5.3 and a 60E and put tens of thousands of HARD miles on it, and never had any problems with the trans. I pull with my 5.3/60E with no issues either.

The OD ratio between the 60E and the 80E is only .05, so that won't make a big difference. I am getting 20-21 mpg on the highway with 3.42's and a 28" diameter tire.

[MONTEZ]

I have personally watched engine dyno's of a stock bottom end 5.3 with a cam and spring package with headers and m-90 ecm make 440hp at the crank. If all you want is 350, then the 5.3 will be plenty. Also the 4l60e would be just fine for it. But if you wanna stay around 20 MPG, then your gonna have to stay with a pretty high rear gear set.

[33shooter]

This is all very comforting and seems that my thoughts were right on. My goal is to drive my truck daily to work and back. I have a 15 mile commute one way on an interstate.

I'm planning on using the DT LSx swap headers, and was considering a cam and spring kit. Not sure what cam specs I want as thats a whole lot more research to try and wrap my head around it. Any other performance mods that I should consider?

What is an M-90 ecu? And is that what I should look at?

I want an iron block, aluminum head motor and would prefer something with the L92/vette heads. The long term goal is to put a blower on the truck when I stop driving it as a daily driver. This is why I was looking at the 4l80e, but if the 60e is fine up to around 400ish at the crank then I should be ok.

As for gears, I was looking to stay around 3:40's and if I need to 3:08s. I'd prefer a 3:73 but I think my mileage would suffer. I'm planning on running 17 or 18" wheels with a mild street tire. Probably TT2's but we'll see. If I go bigger on the tire, I can run a taller gear, but thats up in the air and I'll see where I go on that.

Another question. I have access to E85 and use it in my F150 when I'm around town every couple of tanks. Its cheaper by .30 cents a gallon. On my F150 it is worth it if I'm staying with in town driving as its only a 1-2mpg less. On the hwy with that truck it turns into a dog and is 5-6mpg less so regular is what I use.

I'd like to be able to use E85 in this truck, not exclusively, but on occasion. Please correct me if I'm wrong, but if I were to put a blower on it, couldn't I use E85 also? It is a full .50 cents cheaper from E85 to premium. Just curious, as to what others thought about this and if its practical. I know there are some E85 flex fuel 5.3's but this is just an exploration to see what others think.

This truck is gonna be sweet.

[MONTEZ]

The m90 is from Mast Motorsports. I wanna say the m90 kit runs around 1700 but it comes with a harness and pedal and stand alone ecu. It is the most versatile lsx ecu on the market. With the kit it's a 3 wire hook up and fuel and your good to go. They even offer packages with a cam and springs. Not sure on pricing though.

As far as e85 goes, there is potential for greatness but you re gonna wanna spend the extra cash on a good ecu to make it work for you.

If you plan to go supercharged in the future make sure to run dish pistons.

[33shooter]

Ok, I found Mast solutions ECM. Looks promising, thanks!

[33shooter]

When it's time for the blower, I'll forge the bottom end and rework the heads. If I'm spending 6k on a blower or turbo setup I'll make sure to do it right.

That mast performance set looks nice. I'm gonna have to give em a call.

[glock35ipsc]

I ran the blower on my 5.3/4L60E for about 60,000 miles without problems. You'll love it!

I have E85 planned for mine, just haven't done it yet. It's still under $2 here.

I love the 3.42 in my 85, plenty of power and over 20 mpgs on the highway.

[33shooter]

Ok, which 5.3L would be best? I still want aluminum heads and an iron block I think.

Looks like the Mast ECM is a pretty nice and pricy unit. But I'm not sure it's in the budget. A cam/spring kit should be no issue. Long tube DT headers, and magnaflow mufflers. What other conservative modifications should I consider? Is the weight savings of an all aluminum block worth it? Especially since a blower is possible later?

Any suggestions for A/C compressors? Mounting location? Could I use the one the motor comes with? This is a 70' C10.

[MONTEZ]

Originally Posted by 33shooter

Ok, which 5.3L would be best? I still want aluminum heads and an iron block I think.

Looks like the Mast ECM is a pretty nice and pricy unit. But I'm not sure it's in the budget. A cam/spring kit should be no issue. Long tube DT headers, and magnaflow mufflers. What other conservative modifications should I consider? Is the weight savings of an all aluminum block worth it? Especially since a blower is possible later?

Any suggestions for A/C compressors? Mounting location? Could I use the one the motor comes with? This is a 70' C10.

Go iron if you plan you plan to super charge. Honestly If I were you for now I would find a 5.3 with cathedral port heads and leave it alone. Invest in the m90 up front and swap the rest when you add the super charger. That way you can get heads and a cam that will be best suited for the charger.

[chevydog66]

Originally Posted by 33shooter

Ok, which 5.3L would be best? I still want aluminum heads and an iron block I think.

Looks like the Mast ECM is a pretty nice and pricy unit. But I'm not sure it's in the budget. A cam/spring kit should be no issue. Long tube DT headers, and magnaflow mufflers. What other conservative modifications should I consider? Is the weight savings of an all aluminum block worth it? Especially since a blower is possible later?

Any suggestions for A/C compressors? Mounting location? Could I use the one the motor comes with? This is a 70' C10.

I heard Doc's blocks work for the a/c compressor.

[Juiced06GTO]

Keep in mind that with a 5.3 you will not be able to run the l92 style heads as they need a min 4" bore. The stock pcm's are pretty up to the task, I spent the cash and got HP Tuners so that I can control everyhting on my car. I will be using it once I get my swap complete on the truck I am doing.

[MONTEZ]

Originally Posted by Juiced06GTO

Keep in mind that with a 5.3 you will not be able to run the l92 style heads as they need a min 4" bore.

He's right, I wasn't even thinking....

[33shooter]

Ok, so vette heads don't work on the 5.3? Well that sucks. I'll probably stick with the stock ecm as that will save me a bunch of money that I could use for other items. My truck needs EVERYTHING but a body and frame....and they need work as well.

I'm not a fan of the engine covers, has anyone ever shaved the stock truck intakes down and made them look better?

[glock35ipsc]

Originally Posted by 33shooter

Any suggestions for A/C compressors? Mounting location? Could I use the one the motor comes with? This is a 70' C10.

With very minor modification to the passenger side engine stand and adapter plate, you can use the LS's compressor in it's original location. You will need the following AC manifold adapters from Docsblocks.com, then either make your own hoses, or take your truck to a place that can do them for you. Most all NAPA's around here will make them. With these manifolds, you will not need to notch the frame at all.

docsblocks.com

P/N AA2209, suction side, $14.98
P/N AA2210, discharge side, $19.98



For everything else, you can use the parts that are OE for the truck. Although I would recommend replacing at accumulator since you will recharge with R134A. You might want to replace the condenser too. I replaced mine with a direct replacement for the truck, meant for R12, but it works just fine. I've been freezing my rocks off even in the 100° + temps we have had lately. There is another condenser available that is better suited for use with R134A as well if you chose to go that route.

Originally Posted by 33shooter

I'm not a fan of the engine covers, has anyone ever shaved the stock truck intakes down and made them look better?

I think it was Butcherboy that did this one. I like the idea of it, although I still like the simple one-piece cover myself:

[Juiced06GTO]

Older vette heads (97-04) (cathedral ports) will work on the smaller bore. I believe there is even a company making l92 style heads that will fit the smaller bore of the original ls1's, but the bore on the 5.3 is just to small to accomadate the valves in the l92 heads. This is not really a huge problem as there are a ton of heads that will fit that flow great and will make a ton of power.

Your best bet from a cost stand point would be to pick up some 243 casting number heads, get them cleaned up, and slap them on there. As for a cam, something in the 224-228 range on intake and exhaust with around .550 lift would probably work pretty well. My GTO runs a 232/234 with .598 lift on i/e but with the bigger displacement 6.0. With only 5.3L I would stay smaller to keep it driveable and easily tuneable.

[33shooter]

He put that motor originally in an s10 right? I'm gonna have to do that to mine, I like that better!

Any suggested reading on the ls cam specs or cams in general? I want improved power but want it tuneable and driveable too.

[glock35ipsc]

Yep, an S-10.

I would contact Thunder Racing or Vinci Performance for cam recommendations.

[Ackattack]

I have a couple of buddies with supercharged/turbo charged LS1 cars running 4L60Es. They can be built to handle 600+ HP and are more efficient than the 4L80Es.

My first tank of gas through my 5.3L I got ~16.5mpg with 4.10 gears and a 4L60E. I need to do a little tuning to get better, the headers probably through the A/F ratio off a little.

All of the 5.3L have aluminum heads and most of them are iron blocks. Additionally, you can bore a 5.3L out to a 5.7L when you get around to building your forged blower motor.

[33shooter]

Ack thanks, you and a few others are my inspiration. Im looking more at a 6.0 now, still not sure i want the 5.3. I am going to try and get an L92 if i can find one, we'll see.