New Fuel System Questions

[Dieseldan73]

Hello, finally got my new fuel system complete. Got a Beans sump, -10 to water seperator, Fuelab 41402, 2 micron filter, -8 up to y-block, then -6 to each head and -6 to Fuelab regulator and back to the tank. First question is how much is horsepower affected by low pressure? I always thoughty truck ran great and had a lot of power even though I was dropping into the lower 20's at WOT. It now holding 55psi at WOT and doesn't drop more then 1 psi, but the truck feels like it has a lot more power. I thought I was imaging it, but I took my friend with me who knows my truck really well and he agrees it has a lot more ballz. He says it feels like I changed injectors. Could that low fuel pressure been costing me that much horsepower?
Next questions is about my pre head and post head pressures. Before the pressure at my fuel bowl and regulator were always within 1 psi. Now I have pre head at my y-block and post head at the regulator and the pre head one reads 8 psi higher? They are same sending units I had before and I even swapped them thinking one could be messed up, but they're not. but could it be that the Fuelab pumps so much fuel that the lines coming from the y-block to the heads and the 90 degree fittings are restrictive? Has anyone else have both pre head and post head fuel pressure readings with aftermarket pumps? I set the regulator to the regulator sensor since I want my injectors to have 55 psi, but now my pre head one has about 62-63 psi. Just wondering if this is normal or not.

 

[bootcamp]

I had my sending unit before the heads and it read 60 and then had the gauge set up on the regulator and it read a 5 psi difference and this was with it running. So now i have the sending unit at the regulator after the heads so I can get a better feeling of what is going on with my fuel pressure.

 

[Dieseldan73]

Thanks, I have also sety fuel pressure to the sending unit on the regulator. I figured that's the best for the injectors.