Major Hydro boost issues

[Mlagroue]

Just installed Hydra-tech in 1969 camaro. Brake immediately lock when car starts. Plumbing is correct based on manufacture recommendation. ( Return Tee is close to reservoir).
-1 1/8 Master cylinder. Reading a-lot of forums ect..list of reasons why is long. If i rule out bad unit for the sake of trying to find an installation error, where would you start?
Back pressure from return?
Brakes feel good and travel is nice until car starts and the brakes Pin to the floor. Any help is appreciated.

[Mlagroue]

Yea i bled the system for at-least 20 mins before I started engine, until i did not have bubbles coming in. Yes the fluid does look aerated( light tan color).

[Olds.PhD]

Did you make sure you have a gap between the booster pushrod and the master? I had to clearance mine.

[Mlagroue]

Did you make sure you have a gap between the booster pushrod and the master? I had to clearance mine.

No i did not back check clearances, i figures if it was car specific from hydra tech it should be correct.

[Mr Nick]

No i did not back check clearances, i figures if it was car specific from hydra tech it should be correct.

I've not used him, but I'm told Paul at Hydratech has great customer service. I'd contact him directly if you have not already.

[Hotwire]

Back pressure would cause the pedal to not travel or give you resistance\kick back. The fact that you're pedal is traveling straight to the floor on startup sounds like it's plumbed wrong?

[Mlagroue]

Back pressure would cause the pedal to not travel or give you resistance\kick back. The fact that you're pedal is traveling straight to the floor on startup sounds like it's plumbed wrong?

After speaking with Hydra tech, back pressure was advised was the issue. I completely separated HB. Return from PS return.
Results were pedal did not go to floor but still moved engaged upon start up to engage brakes.
-Next would be to dial down flow valve and possible have to do something about having a larger reservoir.