where does the stock 6 bolt head stop flowing?

[GSXftw]

So Ive been systematically upgrading my car, hitting the track with each mod/shaving time down, I was hoping to hit an 11.99 this year. I did a 12.78@110, that is the first log, 22 psi since thats all the stock WG spring allowed. I upgraded the WG spring, upped the boost to 26, and surprisingly didnt pick up ANY trap speed, ran a 12.61@110, which was pretty much only due to 60 ft. So question is WHY? I didnt drop timing, knock, IAT stayed nice and cool. I see people with a stock 6 bolt running in the 10s with mid 30s psi, so whats holding me back? I do show more lbs/min, but being on SD I imagine its just a calculation and not measured. Relevant mods are-
Cyclone intake (it is actuating right)
BC 264/272
ported 2g ex mani
TL TD05 20g
VRSF, water/meth
The longblock is stock and has some unknown miles. Stock head, valves, TB, ect. It did pop out the dipstick on this pass if thats a clue, but I leakdown tested it and they were all in the 20%s, which is where youd expect it I guess. So what should my next mods be? Thanks for looking

 

[LandSpeed-DSM]

It's definitely not the head

Stock block, 20% leak down, are you on the 1G throttle elbow too?

Full weight car?

What's your 60' time?

Trap sounds about right for a 20G @ 25psi on an old low comp motor in a full weight 1G..

 

[GPTourer]

I don't think you worry about outflowing the stock head until you get above 900whp or something...

At any rate, I think I would be looking into at least a freshened bottom end, like someone's "stage 1" build or go with forged internals before I tried to turn it up to 30 psi.

 

[GSXftw]

It's definitely not the head

Stock block, 20% leak down, are you on the 1G throttle elbow too?

Full weight car?

What's your 60' time?

Trap sounds about right for a 20G @ 25psi on an old low comp motor in a full weight 1G..

Full VRSF kit for piping. Yes full weight car, 60 ft is 1.78-1.85. Just mostly wondering why 4 psi made no difference at all? With my experience that means Ive maxxed the flow on a certain piece and have a bottleneck correct?

 

[Arthris]

Look at the compressor map. I ran a 12.3 at 107 with a Basterd 20G in my 1G. No idea of flow. but ## looking at mid 40 lb a min. 25PSI is probly the max ## gonna get without blowing more hot air. I was also on E85. Probly why I ran what I did. Although a Buddy ran 11.9 on his 20G a few years ago.