Is this motor N/A pr blown ?

Na

Please explain the 684 HP / hair dryer ??

What do you mean? I just posted N/A...

Jim Valako Dart Race heads matched with intake...he is no joke. There are many here on oso to verify. Not sure why you are even going here.

Just went thru this today on my 555 NA motors. -8 or 1/2 from the tank to pump, -6 the rest of the way. 8 lbs fuel pressure at idle per electric guage on fuel dist. line. Your pressure seems low from what I have seen in the past.

As far as your HP goes, 684 NA isnt that crazy to achieve IMO. I get the 509cid limiting factor however I m sure the heads and intake make up a bunch. What carb and compression are you at?

Get your azz in bed, we've got a hard day in front of us tomorrow.

Had to replace my fuel line on bone stock 502 this summer and it was 5\8 or an 10.
your fuel line is probably way undersized, and or pump worn.
edit in tank to low pressure pump

I'm still in Blytheville running crews. Prob won't be home till 2 or 3am. Up at 6 and back to work on the boat though.

Im not knocking on the motor or the builder, those are great numbers for a single carb and no help.

Is there a reasonably priced pump that will support my HP level? It is Gen6 sea pump mounted.

http://www.cvproducts.com/ProdDet.aspx?PN=SPIN-MP-2630