Not sure about my dyno results and wanted to see what others think. Seems low to me but it runs well. Any feedback would be appreciated.

347ci
10:1 even with Mahle pistons gapped rings for mild boost
h beam rods
243 heads CNC ported, stock valve size 68cc chamber
42lb injectors
219/227 @.050 .612 lift 115 lobe separation.
stock rockers with trunnion kit. 11/32 pushrods
stock LS6 manifold and throttle body
stock airbox and filter
1 3/4 American Racing long tubes, 3” x pipe with cats, 2 1/2 tailpipes to stock titanium mufflers
all emissions equipment hooked up
15% larger 8 rib balancer for future blower

383 wheel hp and 353 torque at 6200

Operator said there was a vacuum in my intake which means there was a restriction. KVA result showed him this.

 

Intake, airbox, stock LS6 intake and TB are killing at least 20-30HP. Cam is mild, so I'd expect a lower peak with that as well.

 

Is the throttle body opening all the way?

 

sort of what I expected to hear but thought the manifold and throttle body would support more. I did remove the air filter and made one final pull. It didnt pick up at all.

wow, good thought! I’ll check for that.

 

confirmed it’s opening all the way

 

Without a bellmouth to guide air, just pulling the filter isn't going to do anything. There's a reason FAST intakes and bigger throttle bodies gain a lot on even mildly modified LS engines. I'd at least buy a good cold air intake and see what that nets you. There's also the option of porting your stock throttle body, which isn't that difficult and has shown gains.

 

Thanks for taking time to provide feedback. My goal for this build was to add a supercharger so I'm not sure I want to spend any more money on the stock induction. Will the Throttle body and LS6 intake be a limiter if my goal is 600 rwhp on 91 octane with a blower kit?

 

If you're forcing air through the TB and intake with a centrifugal, it should be less of a restriction, and 600 wheel should be easily attainable. I would still port the throttle body in that instance, however. If you do it yourself, it's free. The LS6 intake is the best flowing cathedral port car intake GM made, so it's not going to be a poor performer on a forced induction build. It's when you are trying to maximize output on an N/A combination that the stock intake and TB become a restriction.

 

Your down on power. Thats where you should be with a stock ls6 with headers and minor mods. The compression is hurting you for sure

 

Plain and simple... It's not moving enough air.

The stock induction system, mild cam and smaller exhaust isn't helping matters any but with the supercharger you should reach your goal.

 

It depends a lot on the dyno used and if it's uncorrected/corrected etc. You can make a lot of power with a ls6 intake, I made 482whp corrected (lost power corrected due to winter DA) dynojet at speed inc back in 2007 cam was 238 242 xer lobes. I've also made 458whp with a ls6 using the same heads that were on the 383 (cnc ported 243's 58cc) on a stock bottom end ls1 in a rx7 with a 228 230 LSL lobe cam. On this particular dyno most heads and cam cars would make 430-460 whp so it's not out of line, a stock c7 Z06 made 550-560whp and other stock ls1 cars make low 300-320.