Hi everyone, i'm just gonna start off and say this is my first LS engine build, so i'm somewhat of a newbie.So far I just have a Gen3 6.0 LQ4 block, and a Gen3 4.8 crank. Now what i'm looking for is suggestions and info on what parts I should use for the build. I have any idea on some parts that i'm going with, Now I am dead set on a destroked high rpm supercharged twin turbo'd engine, looking for about 1300whp and i would appreciate it if nobody tries to talk me out of it! lol. It's going to be mated to a magnum 6-speed and put in my 81 Corvette. It will be a street/strip/autocross car. So please help me out, I'd appreciate any info given!

Compound boosted destroker capable of 1300whp

Block:
Gen3 LQ4 bored .30 over
Block filled to bottom of water pump holes
Katech pinned billet mains
ARP main studs
Piston oil squirters
Athena Oring Headgaskets
Dry Sump Oiling

Rotating Assembly:
Stock 4.8 crank- polished & cryotreated
Lunati 6.300" H-beam forged rods
Pistons- (Not sure what size to get, definitely forged, trying to get 10:5:1 compression, heads will have 72cc chambers)
Super Damper
Bearings-(Not sure what bearings to use)

Valvetrain: 8000+rpm capable
Liberty 255cc 11° Rectangle port heads, 72cc combustion chamber (Bare)
Inconel Exhaust valves
Intake valves- (Hollow stem if I can, if not then i guess titanium, not sure)
Lifters- (Solid roller, but no clue what size or what kind to get)
Pushrods-(Not sure)
Springs-(Not Sure)
Rockers- PRW 1.7 Shaft Rollers
Double roller timing set
CAMSHAFT- (Obviously a solid roller, but I have know idea what specs since i'm going to be running a supercharger and twin turbos with high rpm)

Intake:
Magnuson Lower Intake
Custom supercharger lid with ATW intercooler brick
Injectors- (Not sure what size, gonna run pump gas to cruise, and Race Gas for ***** to the wall)

Supercharger: Eaton M122

Twin Turbos:
Not Sure what size, They will be rear mount, and be able to support 1300whp

Engine Managment: Megasquirt 3 3.57

All right thats all i could think of off the top of my head. Ive had a dream of building this kind of motor since i was a kid, im now 31 with a decent paying job and finally what to achieve my dream. I really appreciate whoever takes the time to do any research for me and help me out with and info, suggestions, and tricks to make my build go smoothly, If theres anything i'm forgetting please point it out. Thanks everybody!

 

You're setting yourself up for expensive epic failure.

Drop the compound setup. I've messed with them. They picked up big power by dropping the blower.
I'm not gonna go find the link but get on google and try to find the Hellion TT supercharged mustang. With the blower it made over 1000 HP at 44 PSI. Dropped the blower and IATs dropped over 100 degrees and it made almost identical power on the turbos at 26 PSI (all of this from memory, numbers might not be exact). 99% of the people who talk about doing them either just have the cash laying around to waste, have built everything else, or are inexperienced and have no idea what they are doing.

Wanting to use an M122 puts you firmly in group #3. Most of that setup it extremely overkill and unnecessary and that's saying a lot coming from me lol.

 

I have read alot about the Hellion setup. I know i could make the same with just twins, but i'm really looking for a uniqueness factor also, I know i'm crazy. I'm also going to be running an standalone interchiller setup, and water meth. and i want the blower for down lo to spool the twins, since im gonna lose torque down low because of the drop in stroke.

 

Awesomeauto knows his stuff. If he says don't do this, and you do it anyway, you are a victim of your own stupidity.

 

I'm not looking for negative responses. i appreciate the knowledge. could you guys maybe just point me in a direction of which pistons to use with my rods, and heads. also if you could help me figure out what stuff to use for the parts that i listed that im not sure of

 

I’m not as concerned with the compound boost as much as I am with the 4.8 crank. It’s the strongest iron crank made by GM because of the shorter arm, but it’s going to be asked to hold 1400+ hp and who knows what kind of torque numbers. I’d definitely look into a magnum crank for a build like this if it were mine. There was a 3.26” stoke magnum here in the classifieds for a long time. Might still be there. It was a great price iirc. Not trying to be negative, but constructive here.
For pistons, you’ll want something coated on top as well as the skirts. Really boils down to final deck height and what cc your heads end up being to figure out, A. your compression height and B. your static compression ratio number your after. Don’t skimp on the ring package with this setup.
For valvetrain call Cammotion or Comp and have them spec you every bit of this except your push rod length, which you’ll have to do your self. Buy the setup as a package spec’ed by a professional and you’ll have no headaches later on. We can all suggest a setup but you’ll get 10 opinions from 10 different members here. Don’t cobble this up. Do it right.

 

OK, lets just say i'm going with just rear mount twins. can ANYBODY help me out with my list of things that i'm not sure of? thats kinda of why i came to this forum, to look for help and answers to my questions. i'm not really looking for people to tell me not to do certain things, i understand that maybe its not the best way, but everything that i have writen down is not set in stone. so far the only parts i have are the block and the crank, and the stuff i have listed is what i'm probably gonna buy.

 

Pistons and valve train are going to have to be custom for the application.
Pick a manufacture and have them make all the important decisions.
Bearings for the most part are bearings... the important part is in the machine work and fitment

Even though you don't want to hear it, I can't imagine any reason in the world to go with rear mount twins over a single???
There is no bling, you have twice as much plumbing to increase lag, and loose heat energy.....

 

This is where I got the idea. Compound Boost ZR1

 

You're using a smaller blower and twice the complexity in a twin rear mount setup than the zr1 link. Your money but it's a bad idea for a bunch of reasons.

 

If you want to do something outside-the-box, consider compound turbos. It's got the potential to give you big power at high RPM (like big single-turbo setups) and still make good power at low RPM (unlike big singles). It'll be a challenge to get all of the plumbing to fit, though.

 

I cannot help you with boost parts selection but I agree with you that you should do you.

 

Are you going to tune this yourself? To get it rolling I'd go ahead and buy two or three good 4.8 long blocks each with 30 day warranties from my local yard right now and just use them to sort out the chassis and this super power adder thing you plan to build!? The kind of attention you want to give the inside of this engine with all of the high dollar internal goodies you can afford deserves to go to a dedicated max effort N/a build or at the very least a very well sorted and perfectly pig rich power adder setup that already runs and drives on an engine that if you are smart you will buy for less than $500 first to set up and mock up and hopefully not blow up! Then all you have to do is a simple long block swap with your dream long block! Get it running right with a nice used engine first before you waste everyone's time ruining a nice motor trying sort out the rest of the things that you need to do! have you seen how cheap these engines can be had in good running condition?

 

Man if you have the money (and it's going to take boat loads of it thrown at this) do your thing. I'm interested to see where this goes.

I wouldn't do it, but I bet our bank accounts look vastly different lol

 

I think this is one of those scenarios that started with "Wouldn't it be cool if..." and then actually falling into the money pit to do it..