stand alone fuel pump, overkill

[jaspermaggie]

I have a 420hp 355 and have a 100 shot on it. It has a mallory 140 pump with a 8 feed and a 6 to the reg. One side does carb and other does nitrous. It feels like the car noses over at around 5600. I think it is bottle pressure but might be fuel. Plugs look fine. I am thinking of doing a seperate fuel pump, or getting 8 to the reg, or doing a return, or doing a mallory 140 just for nitrous. What would you do? If I do a 140 for nitrous that is just on for the nitrous can I use a dead head? Is a stand alone for 100 shot overkill? If I do return with waht I have can I use 8 to the reg and my 6 as a retuurn? Lots of questions thanks

[rustbucket]

do you generally spin the motor higher than 5600 rpm's when just running on motor? Just making sure your cam, heads,and intake allow for more rpm's without floating the valves.
I like 2 fuel systems. With 2 you can tailor the fuel pressure requirments for the carb and the nitrous.
Ive used holley dead head regulators and bypass style. The deadhead will work. It may not hit quiteas hard as the bypass because the fuel pressure will creep up and when you hit the nitrous, it take a moment to settle at its pressure where as the bypass shouldnt creep up at all. But either will work.I would think a 6an line should be enough. Where are you setting your pressure and how are you doing it? A good way to adjust the nitrous fuel is to take your plate and put it in a bucket with the jet you are going to use installed. Spray the fuel and adjust the pressure while its spraying into the bucket. Im not sure if you set it for about 5.5 to 6 lbs if you will be sastisfying your carb wich may want to see around 7lbs. Thats where 2 systems would be an improvement over 1.
I use a 140 just for nitrous. It may be overkill but I had it laying around, so i used it. Its not going to affect the fuel pressure. A 1 gallon cell up front and a holley blue would be fine for what your doing. Both can be purchased for less than $250.
Not sure what else can help you. Maybe some of the pro's will chime in soon. good luck

[jaspermaggie]

on motor it makes power to 6200 max at 5900-6100. I think I am running into a bottle pressure drop. On nitrous I was shifting at 5800 it only noses over sometimes. thank you for the help