I though this combo should make more power?
 

I have a 98 Camaro z28 car that I had a 6.2 built for. The motor has forged Molnar rods custom auto tech pistons 11.8 compression, Trick flow Gen X 255 heads, Cam motion Cam XA230/365-XA238/355- 113+3 TSP 1/7/8 inches headers into a 3 inch Y pipe single out to CME. Nick Williams 102 TB, ported LS3 Intake. I had it tuned yesterday in AZ and the car made 468 WHP, and 436 Ft pounds. I was hoping the car would make 500+. Is there something that can be done to get some more out of it. I will be adding Flex fuel to it, and I'm thinking about adding dual cutouts, Is their something that this combos is missing thats preventing it from making more power? And my next issue is since the swap I can not get the gauge cluster to work. I thought it was something in the tune, but they assured me its not. The tuner believes its in the wiring, but nothing from the the dash was touched the harness is out of a 2002 Camaro that I took the T56 Transmission from. Any help with either of these issues would be greatly appreciated.

Forget the dyno number for the moment. If I had a dime for every time I've seen this I'd be rich lol. Run it at the track and see what traps. Trap speed doesn't lie

Uncorking that y pipe outlet will help a lot. More than likely that outlet drops to 2.5 in. inside diameter.

Put a flowmaster merger in there with a 4in. outlet

so very true.

Its three inch all the way out I'm kicking myself in the ass now for not doing dual exhaust all the way out. I ordered the cutouts yesterday so hopefully it does help. Any ideas about the cluster not working. I know its got to be in the wiring, but I'm a little loss about where to start Its pulling a P0650 code. I know its in the wiring but any ideas where to start, or what something like this would cost to get fixed ball park.

I tend to agree. There is likely some restriction with the current Y pipe.

I have witnessed a non Flowmaster Y pipe setup with 3 inch out said to support 500whp +, gain 20whp with dual cut outs on one of my cars.

Ditch the y, ditch the stock ls3 intake. put it on e85.

Who tuned it?

I didn't ignore the exhaust, I wanted the CME on the car and the exhaust shop I took the car too said that they couldn't get the pipes to fit through the UMI brace off the torque arm, and that it would be really tough to find a shop that could make that fit with out taking the pipe down to two inches and then over the axle. I should have been more patient and just found a shop that could do it.

UMS here in Arizona. he thinks with the E85, and the cutouts that it should make over 5 hundred. So well see. I have the cutouts ready to go, but right now I'm having electrical issues. The gauge cluster is not reading, and i don't want to have to take the dash down but its looking like thats going to have to happen.