I had a thread a little while ago asking about turbo characteristics on a 5.3 that I was going to build, I've decided to bump up to an 04 6.0 LQ4 that I'm picking up this weekend and this is what I have hammered out so far for my build:

04 6.0 LQ4
Twin 7665 Turbos, .81 a/r
Truck Intake
120lb Holley Injectors
LS9 Head Gaskets
PAC 1218 Valve Springs
Sloppy Stage 2 Cam
Comp Cams Rocker Trunnion Upgrade
Gen 4 Pistons/Rods
ARP Head Studs
Double Roller Timing Set
3 Bar MAP

I'm going to be replacing all of the other factory bits and pieces as well like new lifters, oil pump, water pump, bearings, etc, etc and adjusting my ring gap for boost but that's basically what I have together for an aftermarket engine parts list, is there anything that I should add or something on there that's not needed? I've been doing a ton of searching but there's so many conflicting opinions on some things. I'm going to be hooking this up to a 4l80e with a water to air intercooler system, water/meth and a monster fuel pump, I figured since all I can get up here is 93 octane I can use all the help I can get. I just bought a 79 Camaro to throw all of this in, it's stripped down, no interior or inner fender wells, full roll cage, frame connectors, fibreglass hood, etc. previous owner ran mid 10's in it with a nitrous small block.

 

Those are some serious turbos for twins. A lot of dudes are happy with just 1. I think that's enough turbo for like considerably over 1000 easy. So if you don't plan on getting those numbers (considering to. Budget build. You should get smaller turbos

 

I tend to overbuild, I'm usually not happy at one power level for long so I figured this was just basically good insurance to be able to turn it up when I need to. Also since this car is already caged, I know I'll be able to shoot for some killer times at the track.

 

I think the comp trunnions were problematic? I'd do a custom cam imo.

 

04 lq4 may already have gen4 rods. Depending on the miles you may not need to do anything internally, my 04 lq4 had 240k hard miles. It also had a lifter roller completely gone which destroyed the cam. I took the bottom apart and measured everything and it was mint. Rings were already gapped 28 top and 30 bottom and bearings looked perfect. Sometimes you can let the magic smoke out when you dig further thsn necessary.

I agree with previous post those will be huge turbos as twins. The sloppy stage 2 is a great all around cam but has it been tested with twins? Idk you may be the first. Personally id get a specific twin turbo grind or go custom and upgrade to the BTR dual platinum springs.

After i said all that, i understand sometimes you gotta blaze your own trail. Let us know how it works or we will never know!

 

I'll have to check the rods when I get it, this LQ4 has 150,000 miles and runs like a top, I'm driving a 10 hour round trip to get it because I'm getting an awesome deal. Also the 04 2500 that it was in was in mint shape, looked very well maintained and it's an older guy who's owned it since new so it probably hasn't been abused too bad, he decided to part out the truck because the transmission went out in it and he had a newer vehicle anyway.

I'm trying not to over build and get things that are a brutal waste of money when it comes to the engine build so that can get hard at times. When I first started with this idea I had a budget turbo 5.3 in mind, the more I read, the more I found that I'd "need" to do. What started as "throw some arp head bolts on, an ls6 cam, ls6 springs and a 76mm single." Turned in to "crap, this site says you have to do a trunnion upgrade, this site says I need to get a valve job on these 862 heads because the intake valve is useless, this site says you have to buy new lifters because they like to fail on 5.3's, this other one says I need 7.425 pushrods, etc, etc, etc."

So after spending tons of hours reading and researching I ended up easily quadrupling the amount of money I had originally intended to spend putting together my parts list. At this point I already had the LM7 and one 7665 turbo but was told the .81 a/r would be a choke point for a single build on a 5.3. I had the opportunity pop up to buy this 6.0 so I thought about the head work and lack of cubes on the LM7 and just bought the LQ4.

So I thought I might as well just go hard and twin 76mm this thing and put the money into it to build it right. A friend of mine is doing a legit budget 5.3 and he ordered 2 turbos in a drunken "dude, I'm gonna order TWO turbos!" moment so I already have a second one that I got for a killer deal lol.

 

I would replace the lifters, they are known to fail on all the truck engines and less than $100 on ebay. Since you got the heads off get LS9 head gaskets i believe summit has these for less than $50 each, i reused my stock head bolts but it is risky. Head studs are preferred. Go ahead and gap the rings a little looser, the bottom end should look perfect. While you got it apart a new oil pump would be good. throw in a twin turbo cam and some 660 lift springs. Slap it together, get it tuned and let her eat!

Edit: this all assumes gen4 rods. Easy way to tell if the exhaust manifold and lifter valley cover bolts are 13mm its gen4. 10mm on both is gen3 and if its a mix could be either.