New rebuild, strange loss of power

[red5.0fogger]

If the stock air box has the silencer in it that could be costing some power. Mine never had it, iDK what it looks like or how small the opening is. Just an idea.

[Pappacosworth]

Trickflow 170 heads, with 1.6 roller rockers.
I made some years ago 5.0 from my cobra, original gt40 iron heads, lunati stage 1 cam, long headers 330 hp. I have similar calibration on this, this feels worse than stock with 3.73 gears

[wwhite]

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Intake Closing Point (degrees) 
ABDC @ 0.050 lift plus 15 degrees	
				54

Why plus 15 degrees?
Doesn't the cam card show 39, not 54?

[Pappacosworth]

https://uempistons.com/p-27-compression ... lator.html
I think in that point starts proper combustion?

[Pappacosworth]

Few things checked, no help. I measured exhaust backpressure both sides from o2 sensor bungs. Both sides show zero pressure, at idle needle swings from 0-0.2 bar, but 0 at half/open throttle.
Also timing works, I checked with stroboscope that advance moves according to rpm and is correct.

[red5.0fogger]

Say the engine is down 100hp and something major is wrong. I would think it would sound strange. Does it sound normal under load? sound normal idling? Stuck injector or injectors?

[decipha]

Most of the time when an engine is big time down on power its fuel related. Make sure all the injectors are working and that fuel pressure isn't dropping.

[Pappacosworth]

Engine runs fine, lifters are audible but not sounding faulty. Exhaust is quieter than I expected. One cat and chamber muffler / side. H-pipe

O2 sensors show that both sides goes stoichio when cruising. Other side is wideband and driver side is switching fast. Afr doesn't go lean when accelerating to limiter.
I'll check next cam timing and lift again.

[Pappacosworth]

Cam is 4 degrees retarded, I must adjust it again. I checked it many times when I was assembling it. Maybe it was settled properly only after run-in.