Lq4chevy

iTrader: (1)

I have been searching and reading on here for quite some time and this will be my first post. Hopefully not to many rookie mistakes. Before I begin I would like to thank all the members and their contributions to the forums and making this a great information resource.

I started my latest build this year and its time to pull the trigger on building the top end of the motor. This is what I have so far 2006 RCSB 2wd Silverado, truck came as a 4.3 5 speed. Since then I have installed a stock bottom end LQ4 out of 2007 donor truck with the addition of a melling oil pump and LS2 timing set. Im sure I'll take heat for this but I have already completed a T56 swap with F-body gear ratios. I understand the headaches and cost associated with this decision but I have a goal in mind of setting some records as a GM 6 speed truck. The truck is stock trim weighed in at 4600lbs this might be stretch but I would like to have a race weight of 4100lbs. I have started narrowing a 9.5 14 bolt rear end with a 4.56 gear... I know this goes directly against my weight saving efforts but Im a purest through and through and can't get my self to install a 9 inch. The truck will be a 5 lug swapped and 4 linked with a 31 inch tire. I have some 15x12 Racestars and 17x4.5 up front in mind.

With the build details out of the way I would like to get some input from the community on the motor specs I have tentatively decided on.

2007 LQ4 SBE (plans to upgrade with forged internals down the road)
Melling oil pump
LS2 timing set
Custom cam will be spec'd by Brain Tooley or John Bewley
Stock casted LSA heads
Hollow stem LS3 valves
BRT .660 platinum dual valve springs
LS7 lifters
Stock L92 rockers with a trunion upgrade
LS9 head gaskets
ARP head studs
Holley Hi Ram manifold
DBW 102mm throttle body
Billet wheel S485 with a 96mm turbine V2 race cover and 1.10 A/R T6 exhaust housing. John Bewley spec'd that turbo for my setup
Custom built turbo kit with forward facing headers
No plans for the fuel system at this time

I have a few specific questions that Im in need of answers. First after speaking with John at liljohnsmotorsports he advised me against a square port top end but there is something inside of me that really wants to try and make some big power with a square port head. With that being said is the added strength from a LSA casting worth the flow restrictions of "the wing"? I've read but not confirmed that a LSA head flows about 25cfm less compared to a L92/LS3 head. Possibly the LSA head may restore some of the low end torque I'm sacrificing?

I think I already know the answer to this but is the HI Ram a huge mistake? John Bewley made it clear to NOT run this intake, reasons being the large torque losses. My reasons for wanting to run it are silly and aesthetics are coming into play. Obviously there is a "cool factor" with the intake but Im also attracted to the fact its cast aluminum and I can modify and customize it as needed. For instance I can tuck or hide the map sensor or vacuum lines anywhere. I've even flirted with the idea of doing an A2W intercooler down the road or maybe even a nitrous plate. Basically that intake leaves a lot of doors open and would really set-off the engine bay or do I need you guys to talk some sense into me and run a stock LS3 intake?

What compression ratio should I expect? I was thinking it should be pretty close to a stock LQ4?

What would be a reasonably safe RPM to spin this at?

Please share your thoughts and opinions on what you think I've done wrong or could change. I know this is a bit long but I really do appreciate the feedback!



Engine bay.

Filling original shifter location before paint.

3d printed cup holder with removable shift boot ring. Copied the factory snap in style of the F-body boot

Needs to be sanded flat and painted. F-body boot was a real close fit but ended up having one made

Prepping rear end to be narrowed and 4 linked

Beav

I am absolutely no value as to any of the questions that you need answered. Having said that, I truly appreciate your willingness to chronicle your journey as I will be following it closely. I've got no intentions of any "max effort" build such as yours, but am extremely interested in a 6 speed conversion. Subbed & excited for your progress. Best of luck, please keep great notes... I'll have questions in the future.

Beav

Lq4chevy

iTrader: (1)

Thank you for your support!! Im eager to get this thing back on the road and start breaking things hah.

As to the 6 speed swap let me know any questions you may have down the road. I think starting with a 5 speed truck made it that much more simple but I know auto guys accomplish it all the time.

Hopefully some more guys(or gals) will chime in soon and let me know if Ive made the right choice with my head and intake selection

03sierraslt

iTrader: (22)

Lq4chevy

iTrader: (1)

Phase one which would include stock internals I would like to see 800ish to the tire and break into the 10s

Down the road a built 370 that could handle more boost maybe try for high 9s. I like the idea of a fast stick shift truck not sure what the record is if there even is one??

wretched73

iTrader: (1)

Seems like you already know this but the T56 will have a hard time staying together. All that power and weight is hell on it. Look at Atomic Fab for the clutch pedal bracket, something you will most likely need.

I believe George C tried going the T56 route for a while and finally gave up after all the issues he had, but I'd look back at his old build threads to try and help you plan out your build

1FastBrick

iTrader: (17)

Thread Moved Per your request

The_W

I swapped from a auto to a GTO t56 in my rcsb. Been good so far, but of course I am not running boost on it. If you are strictly going to drag this then its a gamble on how long it will last but you have to pay to play at that point. I have seen videos of high HP ctsv's running their stock t56 on drag races strictly, of course then they are lighter. I got atomic's clutch pedal bracket which will be a life saver so you don't push your clutch pedal through the firewall. Should be interesting build

Lq4chevy

iTrader: (1)

I voted in that poll Atomic put up some time ago and will be getting a clutch bracket down the road! Great product/idea on his part!

The trans I have is a used unit I got on craigslist for a pretty good price. He said it came out of a running and driving car but I'll be the judge of that haha. I more wanted to get my hands on something for the mock up and to set pinion angle. I know a stock T56 will be short lived but it will meet my needs for now. Its just a matter of time before I make some calls to RPM Trans and Monster Clutches

Lq4chevy

iTrader: (1)

So no one out there has any first hand experience on running a holley hi ram with stock cubes and boost??????