Please help with a LS carb build.


I am redoing the 07 6.0(364) Iron GenIV block in my 69 Camaro and I'm looking to add a couple of ponies while keeping it reliable. My last combo was a stock bottom ended (only ARP rod bolts added) 6.0 with a Comp Cam 234/238 .595/.605 115 ls cam with CNC ported 243's. Breathing through a Vic Jr and a Prosystems 4150 carb. Spark was controlled via stock coil packs and a MSD 6012. It engine Dynoed 527hp and 470 lbs tq. Trans is a Hughes th400 with brake, 3500 stall 10 inch converter spinning through a 12 bolt with 3.73's. Using 28x11.5 ET Streets weighing in at 3600 this combo netted me 11.4 @119 and 10.6 @130 on a 100 shot through a NX plate on pump gas. I drove this car all over without a single problem on pump gas. This year I'm looking to change the following. Here is a list of parts I already have. Please let me know what you think and what you would change if anything.:

Wiesco +12cc 4.00 forged pistons
Eagle 6.125 rods with ARP 2000 rod bolts
Morel Lifters
Keeping the stock crank and stroke
AFR 225 66cc Heads
Diffrent cam ? Which cam would you recomend ?
GM L92 Head gaskets or Cometic .074 Head gaskets to lower compression a little, to make it more pump gas friendly ?
More N2o. 200-300hp on race gas of course.

I'm still looking to drive this car on the street as much as possible so I was leaning towards a thicker head gasket to drop a little compression. Should I even use the +12cc pistons or just sell them and get flat tops?

I would like to make 600+HP at the crank with my next combo on pump gas if possible.

I plan on running this above combo for the next two seasons and then changing out the pistons for 4.030 -11cc Wiseco pistons ( I already have them) and run a blow through carb 88mm PrecisionTurbo setup. Same block,crank, rods, heads and intake.

 

Damn! 600 hp from a 364? That's niiice!

 

I will be picking my car up from SNL Performance in a couple of weeks, and we are expecting ~525 at the wheels with this combo. I think you may want a littl larger cam to start with. I will be running an iron 6.0 (.030 over for 370ci), smilar internals as you, PRC 227 heads, and a SNL v.X cam with a ported FAST 92.

It made 480 at the wheels through a M6 with the cam-only set up. Your TH400 will eat up a lot of that though. 600 at the flywheel is approx. 500 at the wheels.

 

I no longer have that cam. I think I might need something in the 240's range to acheive my goal.

 

mine is a mid 230's/ low 240's on a 112.

 

I was leaning towards a MS4 cam but I'm not sure that it is going to be enough to meel my goals. I may need a larger custom cam.

 

I built my LQ9 408 forged short last year through Late Model Engines when GM HighTech had it featured. I then called jon janns at texas speed an had them spec my out a big cam for a single plane sky screaming rpm cam with a lsa wide enough for a 200 shot with a decent set of milled Ls3 heads, 1-7/8 hooker LT's, TSP True Duals, 12-bolt, 4:10's, L76 intake/92mm TB Ported, fast 65lbz, walboro 225Pump. Then car fell flat on the dyno after about 4100RPM, but it made 527/475 with alot more left in it because it's made for a short runner single plane intake not a long runner stocker. So when the rest of the parts get on the car then i'm sure it'll make closer to 600, but it's almost unrealistic for a small cube to make then much power N/a if it's not revving sky high to the breaking point of most components. Altough there are a couple of 346/370 cubed cars running around STL that make between 475 an 506. It can be done never doubt the LS-Motors! Nothing ties a bowtie in my opinion with any Ls application. Just have to make sure you match every component to make the most of the power your looking for.

 

I'm looking to make close to 600HP at the crank not the wheels. It should come out to close to 500HP at the wheels.

 

MS4 would get you awfully close with the right set of heads, but a custom cam would be better. I think you are in the right range with the 240ish duration. You are really only looking to pick up 75FW hp over your old set up, and a cam could be a good chunk of that. I would be looking at something in the .650 lift range. Then maybe some CNC work on the heads and see where you're at.