Does the 450 have a check valve? I'm getting a long crank in the morning or after the car has sat for a few hours. The fuel pressure seems to bleed off right away after the engine is off but if I start it shortly after being off say < 1hour it starts up right away. The longer it sits the longer it takes to crank. The only thing I can think of is the fuel supply line in the tank or the pumps check valve as the car started great before the swap. I used the stock fuel supply line which I heated with a heat gun to fit it on the slightly larger barb of the 450. The seal seemed good but I'll have to pull the pump again to see