I think you're both right.
The rails are fed by one source (into the left hand rail) then it is transferred to the right hand rail (at both front and rear) and then out the right hand rail.
I guess yes they are parrallel whilst the fuel flows in a series way. I hope that all makes sense.
As far as why I'm modifying my fuel rails it's because it looked like something to do!
I'm only running 420cc injectors so can't get much over 600-650HP even with increased fuel pressure.
I just felt it would be a challenge to see how big they could go and retain the stock look of the rails. It would be fun to tell people they can flow enough fuel for 650HP. At least I'll know it's one less item to worry about restricting what I can screw out of the engine.
My current set up is a stock Crown engine with CAI, BFI & Headers into twin 2.5" cat and a single 3" system to the rear. At a guess I have 300-310HP at the fly wheel.
1,000HP looks like fun but finding a 4x4 transmission to cope would be near impossible.
I figure with Kelford head and cam work, Ross 8.5:1 pistons, Some tough rods, Motec management, a mega ignition system and the Eaton pumping out 14lb a 1,000 may???? be achievable.
I want it drivable and not a HP show case so I don't see me in the race for the prize. I'd rather have 650 usable horses over 1,000 unbroken, difficult to handle horses.