I've had a 350 with 305 Everything hooked to it, Now Everything is 350, besides the Fuel Pump. When Going up a Hill or something if your going 30 and hit it to WOT it pulls for a split second and then theres Nothing.. the tachometer reads 5500 rpm for a second and then it up shifts and it pulls a bit. However at lower RPM's it Pulls pretty Good..

So, Is my 305 Fuel Pump maxed out?

 

I will assume that you are running a 350 TBI with the 305 injectors and tune? If so your problem is not fuel related (well it is one of your problems) but more so you are running the stock chip with your new set-up. The stock calibration for the LO3 is blind to any changes you make (ie 350 set-up) and will run like death until a new chip is burnt (assuming fuel modifications are also made.).