I am ready burn my truck to the ground

I have a 02 Silverado z71 With a new 408 11:1 advanced induction full race ported l92 heads 275cc it has a tourqer v2 cam. And a 4l80e with a edge 3000 stall.

The truck run and drives fine and shifts great. But the problem is on the dyno. It made 371/378. First pull them we opened the cutout and lost 20 hp And stayed there. 350 was as much as we could get it yo make with matching tourqe

It is firing on all 8. The tranny looks good all the way around. There is no heat build up any where in the drive train that we can find. I changed the oil. And there is nothing bad in the oil. I sm at a lose. I don't know what to do somebody please help. I know a 11:1 408 with race porter l92 heads will make more than 350/350

 

Was that locked?
Convertor could be junk and it's blowing through

 

Ya the convertor was locked

 

That's something else my tuner said it's eating enough fuel and air. That it sould be making 520 rwhp

 

sounds like its not getting any air to or through the motor, whats the top end like?

 

What intake, throttle body, & filter setup are you running? What AFR and timing at WOT are you seeing?

Can you post the dyno sheet??

 

It is a 92 mm tb a l92 intake The cold air intake is just a eBay one. But it's a big tube and a k&n filter

I am not even sure how much how much timming it has. Every time we tried to give it more it just kept losing power.

 

Cable or drive by wire throttle body ? You getting 100% on your TPS ?

What's your fuel system consist of from pump to injectors ? Fuel psi ? AFR ??Give us every detail of your setup

I know this is basic stuff that you and your tuner probably know but we have to start somewhere .

 

It's cable. the tps is going 100% It has stock ls3 injectors l92 fuel rails corvette fuel fillter with the stock 02 Silverado fuel pump.


tried everything from 12 to 13.2 afr and 20 to 28 on timing. Nothing made more than a 5 or 10 hp difference.

 

We need