Yup, like these from CP.

http://www.cpperformance.com/c-500-f...s-returns.aspx

http://www.cpperformance.com/images/.../620-76300.jpg

that would be it.I made my own,but of course I have access to all the equipment.sometimes its just easier to buy.

I'd head for efi at that level.

OK, so I have my other thread going on where several folks are advising that I sh!tcan my electric pump and install a mechanical pump. I took off a mechanical Holley that looked identical to that six valve pump that MT posted. I know I will have to go with a composite or bronze tipped pushrod with my billet cam. Will I need to run a regulator with the six valve pump? Will #8 lines coming from the tank support 580ish HP?

FWIW, I was running that mechanical pump with a Q-jet on my 454. I'm guessing it just looks like the six valve and is not putting out the same pressure, because I don't think the needle and seat on a Q-jet will take much pressure before it blows off the seat. I'll have to pull it out of the attic and take a look at it.

No, I haven't yet. Was planning to take it out today, but work got in the way. Just thinking ahead in case.

Qjet handles decent psi.

I like mech pumps over electric, but, did you prove your electric wasn't keeping up ?

No, I haven't yet. Was planning to take it out yesterday, but work got in the way. Just thinking ahead in case.

WOW did not expect this, a lot of great info. Only now I have a lot more to think about, but I am leaning towards Teagues or Claysmith's pumps. Just have to figure out how to get it to fit between sea pump and block. I do have one more question, It seems that the lines between the tank and the carb have to be large, but the opening at the needle and seat is something like .030 so why do you need large lines to push through such a small opening. Just trying to understand.

Randy you pretty much answered your own question. You are pushing the fuel through the seat not pulling. The smaller the hose/ fittings and whatever b4 the bump create restrictions and reduce the efficiency of the pump. If you feed the pump with a small hose then have a larger hose on the outlet side of the pump you also reduce the efficiency of the pump because you have to fill the larger hose before the pump can make pressure to go through the seat. It's the same thing if you do a regulator b4 the carb you are pushing through a small oriface then filling a larger hose b4 you can make pressure to go through the seat. If you use a regulator b4 the carb (I use it after) all you need is -4 after the regulator. I've seen a 3000hp motor run with -6 after the regulator and -4 on the dyno. Believe it or not it made a hair more power with the -4. I think the largest regulator out there has a .125 hole in it.

Typical Holley N+S is .110. Many use up to .130". Remember times this by two since the Holley has two of them.

-6 to -8 into the carb is fine for 99% of Performance carb'd marine engines.

We don't have to fight high acceleration G's like automobiles, so that makes it easier on our fuel systems.

Edit in: We do average a ton more gph though. LOL.

You must have never rode in my 240 Baja. You had to fight not to flip over the seat when I hit that thing. The whole boat would leap out of the water. There was no getting on plane :-)

I'll be more specific than just saying automobiles - street/strip and more specifically drag cars.

Example: A 600hp motor accelerates lot more hard in a suspensioned / tired car than the same motor in a boat can ever think of.

That's what I was referring too.

Just to be clear.

Not to take away from boats.

Sounds like I should have ! Would have loved that !

Edit in: Double post.

118 - .101V Viton Stock Holley. For use
in low output motors, 450 HP and below,
using 4-barrel carburetor. Useful in
preventing high RPM enrichment on
speedway motors with restrictor plates.
Flow capacity 125#/hour @ 7 p.s.i. and
.25" float drop.

118 - .110V Viton Stock Holley. Used in
most applications, up to 650 HP with
4-barrel and to 400 HP with 2-barrel.
Flow capacity 175#/hour @ 7 p.s.i., .25"
float drop.

118 - .120V Viton Stock Holley. Used in
most applications, up to 775 HP with
4-barrel and to 500 HP with 2-barrel.
Flow capacity 215#/hour @ 7 p.s.i., .25"
float drop.



118 - .130RV Largest Viton needle and
seat available. Recommended for high
output 2-barrel motors and single 4-barrel
motors producing over 750 HP. Will flow
275#/ hour @ 7 p.s.i. and .25" float drop.
Will not hold idle pressure above 8 p.s.i.

With that information, lets say you have two .130 needle and seats to provide fuel to. .130x2=.260. Thats a little over 1/4'' or .250 diameter for the 2 needle and seats. Now, the smallest diameter in a #6 line, is .30. A #8 line, is .390. A #10, .48. Not talking about the hose inner diameter, but the actual size of the thru hole at the flare.

Now, Lets say your engine NEEDS .130 seats, to provide enough fuel to the engine. You can see, where a #6 line, with the same 7lbs of pressure, will work, as it should be large enough, barely. A #8, even better. However, that is on the PRESSURE side of things. The inlet side of things, doesnt move as much as fuel since obviously its not under pressure. Therefore, you can see where a #6 would not suffice in that situation.

So basically, when it comes to fuel lines, better off erroring to the large size is always a good idea.

Yup, line length, bends, turns, abrupt flow direction changes, etc all effects things.

Let's keep the good info going.

Don't forget to line up the windows of your N&S with the inlet of the bowl when adjusting your floats.

Some N&S companies are thoughtful enough to line the windows up with the flats on the adjusting nuts but not all doe this.

Just a tech tip while on the subject.

Just putting this out there. Not all -an fittings are created equal some are high flow some not. All are overpriced.

MT you can't figure it that way....Its pie R squared... ie: take a .130 needle .. it would be .065x .065x 3.1415 =.01327 times two needle & seat per carb = .02654; now a 1/4" hose or tube would be .125x.125x3.1415 =.04908. Its almost double

Makes sense. I guess you need to look at the orifice as a circle, rather than just the diameter.

So, the question is, if we know lets say a .130 needle and seat can flow roughly 275lbs per hour, or 45 gallons per hour, times 2 for a single carb.....What size fuel line does one need to be able to move more fuel or at least keep up and move 90 gallons per hour, with the carb at 7psi of pressure? Then we need to calculate losses for restrictive fittings, bends, length of line, and so on. Thats for the pressure side.

Whats the calculation for the inlet side of the pump, when dealing with suction?

Correct . Can't go by diameter. We want to go by area.

Thanks, easy to forget.

MT, I believe Aeroquip has a hose size chart for fluids. See if you can find it. I'm out for tonight. Later fella's. Good discussion so far.

MT Problem with the suction side of the fuel pump is, there are so many variables, ie; length of draw, material & resistance being drawn threw, size, length & material of pick up. micron & filter size inline , number, type & size of fittings, G forces.............. you get the Idea here.. If you have all the above, there is a formula. But off the top of my head .... sorry its not in there, LOL. We all know that in most cases you can get away with # 10 line. Lets face it most tank pick ups are between 3/8 to 5/8"... so on the suction side its not going to do much, going way bigger then your pick up size... That being said, if you have too much restriction on the suction side of things ( not to forget vent sizing) you will see it in you WOT fuel pressure, and lose thereof.

I don't know what regulator you use . But any good one will have at least a .437 orifice. If you size it correctly having it before the carb is just fine. Otherwise I totally agree with the above.

Maybe I was thinking of the size of the hole in the little holley regulator everyone uses and wonders why the have fuel pressure problems. I used to know all that stuff but its been years since I was playing around with it. I know what works and doesn't work so the rest of it is elementary.

The information on this site is unbelievable, ok so I am going to run -10 line from tank ( making sure pick up is big enough ) to filter inlet -10 from filter outlet to pump inlet then -6 to carb. That should be more then enough to feed 800 hp 598 ci motor. The problem I still have is how do I mount the mech. fuel pump to the block with the sea water pump in the way. Is there a different type of sea pump that I can use. Also I have never seen the type of sea pump that is on this boat, ( just bought it about 3 weeks ago ) It has water inlet and outlets that face the block instead of going straight back. I would really like to run a mech. pump but its looking like I my have to run a elec. just because I cant mount the mech one. Any ideas....

Can you post a pic of what you have or email it to me and I'll post it? I have no idea what kind of sea pump you are talking about.

Also, for what its worth, I personally would run a -8AN line up to the carb. I mean, what ya saving by going with a #6, 12 bucks? Heck alot of the nice dual feed premade carb fuel logs are -8 anyhow. Just my opinion on that anyway. I am no engineer.

I've used these on some single carb setups. They have a 1/8 NPT gauge port too

http://www.summitracing.com/search/p...4%2B4294949389

I'm using a fuel log exactly like the summit piece MT posted the link to. I'm planning a -8 for all my fuel lines. I wonder if I should upsize the tank to water separator line to -10. I was thinking -8 as the pickup is 3/8 NPT on a 1/2 tube in the tank. I plan on a straight 3/8 NPT to -8 to a long radius 90 degree fitting on the supply host out of the tank.

I bought a 0 to 15 psi fuel pressure transducer for a dash mounted fuel pressure gauge. The transducer was twice the price of the gauge. Go figure. That said, I'm going to feel good being able to watch fuel pressure at the helm and at full load and when running hard.

I should add that the engine will be a 517" NA piece. Relatively mild at around 650 to 675 HP.

in my 1200 hp supercharged engines i run a -10 from tank pickup to filter head,then-10 to my a1000 aeromotive pump then-10 to my fuel log,then-6 to each fuel bowl.my regulator is behind the fuel log with-8 line back to tank.at WOT my fuel pressure never goes below 6.5 lbs.i am at 8 lbs everywhere except WOT.

A bought a fuel log off ebay for $50 it looks identical to the $400 Aeromotive log and functions just the same. I can tell you how many time I had the bowls off my carb and never had to take the log off. I have -10 to the log fuel regulator hangs off the back and then the return. Nice thing about the log with the swivels is if the starboard valve cover needs to come off I can swivel the log up and get the valve cover off. Couldn't do that with my old setup had to disconnect the fuel line. My buddy has a holley log that does the same thing that mine does but he has never taken his bowls off because he thinks his Nickerson carb is perfect (you should see the plugs).

Nickerson really sold alot of Kool-Aid to guys over the years !

Haha. Called him up a month ago cause I wanted to dyno two motors. Wanted a price and to see if we could get them done in one day. No tunning just couple horsepower runs. Never got either of my ?s answered but got an ear full of how great there cams were, carb makes 25 more hp than anybody else's because they port them (get real man I've seen what they do) and by the end of the conversation I was told that I needed to put a blower on my motor. WTF! I just wanted to use your dyno for the day. Didnt need there advice or smoke up my azz.

Sounds about right!

Mild Thunder I took a pic of the sea pump, trying to post it. I wish I would have know how you guys felt about Nickerson before I had them do my carb. I cant say I was totally thrilled with the results for the money.
I am also going to run -8 lines to the carb. How do you mount the regulator at the back of the fuel lines and keep the press at the bowl at 7 to 8 psi. doesn't the press. get regulated after the regulator. Sorry for all the questions
but I want to learn and want to do this right.

Randy I will have a good mark iv pump for sale in a week for so if you need one. Nickersons stuff isn't that bad but it is hit or miss. For what he charges you can almost buy a new carb that will work as good if not better.