I have a Pontiac 455 approx 425 HP w balanced rotating assembly 540/233 cam Aluminum intake 750 Holley double pumper and Headers. Heads ported polished and matched to intake
I am looking for the right fuel pump. I found a tubine style inline at NAPA for 56.00 but it's flow is rated at 4-6 PSI
am I going to run out of fuel at say 5500 to 5800 RPM? or does PSI really matter that much anyway.
I like the Style and price of this unit but have no previous experience with that much HP
Thanks

You need a pump that flows at least 225 lbs per hour at 6 psi. So you need to look at the flow chart or written specifications of the pump to make sure it meets those specs. Some pumps will be rated at a lbs per hour rate based on free flow (no pressure). That data is not worth $hit. You want to know the flow rate at the minimum pressure needed at the carb, which is typically 6 psi or so. Rule of thumb is about 1/2lb per hour of fuel per horsepower.

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70 SS 454 CI Dynoed 684 HP, 702 TQ All Aluminium Fuel Injected Small Block , plus 200 - 500 HP NX nitrous system.

Ok that part makes sense 1/2# fuel per hour per horsepower. and 6 PSI is pretty standard pressure even for mechanical pumps.

That pump at NAPA doesn't run that much fuel per hour.

Ive seen some TPI and TBI setups with that rating per hour but from what I understand their PSI is much higher. will I need to have a fuel regulator at the carb and a fuel return line to the tank so that my carb doesnt flood at less than WOT?

First of all, congrats on staying with the Poncho engine. You will find that the engine runs out of breath with that cam under 5000 RPM, but no worries, just shift it to the next gear rather than rev it out.

You may want to consider a high output mechanical pump for simplicity and quietness. Carter P/N M6907
For electrics you will find all sorts of suggestions and all sorts of prices.
The Carter street/strip electric is rated for 7 PSI and should work fine, no regulator and just a 3/8" steel fuel line from the tank forward. It may cause fuel starvation with long "foot to the floor" runs. P/N P4594
The Holley Blue is probably the most popular bracket racer pump, comes with a regulator, and will work flawlessly, but is rather noisy.
The Mallory pumps are more expensive but are quieter.
There are of course many other makes out there.
I don't believe F.I. style pumps are designed to be used with carbs since F.I. typically uses a return style regulator. F.I. also uses a lot more pressure to atomize the fuel better as it injects it into the intake plenum or runner.
It all comes down to what you want to accomplish. For a street car I prefer a mechanical pump, no wiring, no hassles.

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Custom Auto, your source for quality machine work, cores and new parts at competetive pricing right here in British Columbia 1-888-563-4050
A Canadian, EH? (with a 10 second street car)

Thanks for your post Rustbucket, I was hoping you would respond.

The friend I got this motor from is from Oliver BC he was running a Holley electric
the red pump I think but he forgot to include it with all the other stuff I got in the deal.

The Napa Turbine pump said 6 PSI I am also thinking of switching the intake back to the stock unit I currently have on the 400 Pontiac that is residing in my T/A right now
It also has an Edelbrock 1904 Qjet 795 cfm.
Would That combo run/Idle better than the holley as I know that would definitely fit under my shaker hood?
I dont really expect to be bracket racing the car but I do likes to go fast.
I probably should mention I have installed rhoads lifters for a little better Idle quality
Thanks

Strongly consider the high volume mechanical pump, it's self regulated and will work perfectly for what you need.
The Q jets are a little harder to deal with when using a lopey idle style cam but a little extra time tuning and you will be happy. I would do what it takes to allow you to reuse the shaker scoop.
Long live Pontiac GRUUUUNNNTTT!!

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Custom Auto, your source for quality machine work, cores and new parts at competetive pricing right here in British Columbia 1-888-563-4050
A Canadian, EH? (with a 10 second street car)

Since the engine was previously set up with an electric fuel pump I am wondering if any parts are missing as the fuel pump boss is blocked off.
when I had the block apart there was a round cup on the end of the cam where the bolt through it was off center I am assuming that was what the fuel pump push rod is actuated by. Although it seemed a little thin walled for the job. so I think if I did choose to go mechanical (which is the way I'm leaning now) I guess all I would need is the push rod and a carter super street pump right?

I really appreciate the advise
Thanks

I'm a little rusty on the mechanical setup with a Yak but seems to me the lever is a super long one, no rod required. The offset circle is indeed the eccentric!

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Custom Auto, your source for quality machine work, cores and new parts at competetive pricing right here in British Columbia 1-888-563-4050
A Canadian, EH? (with a 10 second street car)

Your right I was looking at a Haynes Manual for Pontiac and they were showing a picture of a Small Block Chevy.
Pretty sad they can't even use the right picture.
Thats why it wasn't adding up when I was looking at the pumps online
Thanks again