If Dupont Marine would go full time there would be a lot happier boaters in our area!

1/2" is the best bet. Also you can run the electric pump into the manual as a boost pump, just regulate it down to 8-10 p.s.i. and you will have no problems.

my merc 600 sc's run 3/8 fuel line with merc manual pumps of of the sea pump and they hold 5 lbs at wot (4-5 lbs of boost) for as long as you want to hold it stock carbs(700 holleys)
on my 540 i ran 1/2" line with a big mechanical pump (130gph) it held 7.5 lbs at wot more than enough for 6-7 lbs of boost and 900 hp
it really depends on how much hp you are going to make?
good luck

fuel pressure is one thing but does it have enough volumn??? im not so sure about that


***COME GET SOME***

hmmm - is there ever too much volume? Give the pumps what they need...

Anyway, I found a local fabricator that will make what I need. Good prices, and fantastic turnaround. In case anyone ever needs him, he's listed as "Dave Howard" on the following web page..
http://www.geocities.com/richmondpba...?1010510815387

if it doesn't have enough volume it won't maintain the pressure i would go with half inch but they didn't on the 600 sc's?