Fuel hose AN6 or AN8

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F21

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Putting my duster together debating on what size fuel line To run
340 B1 engine About 525 hp I have a fuel Cell in the trunk and was going to run AN6 to the Holly blue pump then to filter and up to regulator then to each bowl on the holly I ordered the AN6 when I got it damn that is small 3/8 so now I’m thinking send it back and get AN8
What are your guys thoughts
 
the dash number on the fitting and hose is 6/8" or 3/8" If used on the street mostly the 3/8" fuel lines are good for 600 hp. I am running the Fast fuel lines, which are 3/8" on a 560 hp 408.
 
F21 said:
Putting my duster together debating on what size fuel line To run
340 B1 engine About 525 hp I have a fuel Cell in the trunk and was going to run AN6 to the Holly blue pump then to filter and up to regulator then to each bowl on the holly I ordered the AN6 when I got it damn that is small 3/8 so now I’m thinking send it back and get AN8
What are your guys thoughts
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You are fine to well over 600 hp on number 6 lines if the rest of the system is up to par.
 
So you guys don’t think I need to get the 8 I should be fine with the 6 Also what are your opinions on which pumps and I do not plan on running a return line either Thoughts
 
F21 said:
So you guys don’t think I need to get the 8 I should be fine with the 6 Also what are your opinions on which pumps and I do not plan on running a return line either Thoughts
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6 is plenty. Not sure on what pump is worth the money. Others can chime in on that.
 
I would do the -8...better to have more volume and not need it. I run -8 on mine, but I'm also on e85, so....yeah.
 
-6 AN is plenty for the discharge side, but I favor -8 on the suction side to feed the pump. I'm sure that -6 is more than adequate, but being that electric pumps work best with flooded suction, the -8 is a little extra insurance for fuel available at the pump.
 
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flyfish said:
I would do the -8...better to have more volume and not need it. I run -8 on mine, but I'm also on e85, so....yeah.
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Normally I would say -6 would be fine. But this guy here ^^^^^^ races a LOT. If he thinks -8 is better, that's what I would go with. Look at it this way. If you ever upgrade to more power, the -8 will already be in place. Your fuel system will be THERE.
 
Interesting Garrett so you are saying 8 from the cell to the pump then after the pump run 6
 
AN8 to and from the carb . Put the regulator on the return.

With this new fuel you have to keep it flowing or it will boil if dead ended at the carb like the old days.

The regulator is different when using it on the return. You cannot use a standard pressure regulator as used before the carburetor. The AN8 fuel line on my car goes right to the carb from the fuel pump the back to the tank after the regulator. Big difference in performance.

One reason they make these fuel lines.

Steve 107.JPG
 
Oldmanmopar said:
AN8 to and from the carb . Put the regulator on the return.

With this new fuel you have to keep it flowing or it will boil if dead ended at the carb like the old days.

The regulator is different when using it on the return. You cannot use a standard pressure regulator as used before the carburetor. The AN8 fuel line on my car goes right to the carb from the fuel pump the back to the tank after the regulator. Big difference in performance.

One reason they make these fuel lines.

View attachment 1715530961
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Right! It has to be a return style regulator to run in the return line.
 
F21 said:
Oh **** are most of you guys running a return
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A return system is not an "oh ****" moment. It's one of the easiest things to do on a car and you should have one.
 
Your fuel is limited to the size opening on the fuel bowl. Everything else is a moot point.
 
I use 6 on everything under 500 HP and it works fine,
-6 is actually 11/32 I.D. = .343". -8 is actually 13/32 I.D.
= .406"
 
If it was me I would run 8 so you have room to grow. Heck when I did mine six years or so I ran the newer black hose in 10 rear to front and ran 8 to each carb. Back then I was running pump gas BP93. Now with alcohol I’m super glad I planned ahead.
 
Oldmanmopar said:
AN8 to and from the carb . Put the regulator on the return.

With this new fuel you have to keep it flowing or it will boil if dead ended at the carb like the old days.

The regulator is different when using it on the return. You cannot use a standard pressure regulator as used before the carburetor. The AN8 fuel line on my car goes right to the carb from the fuel pump the back to the tank after the regulator. Big difference in performance.

One reason they make these fuel lines.

View attachment 1715530961
Click to expand...

That is how all the newer fuel injection cars are set up, regulator in the return line.
 
brian6pac said:
That is how all the newer fuel injection cars are set up, regulator in the return line.
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Well......sorta. Most of the newer GM products have a fuel filter/regulator unit. Has one inlet and two outlets. One outlet going to the engine and the other is an orificed return going back to the tank. That's what pretty much all of the modern aftermarket fuel systems are going to. I've built a few of them recently myself. It's a nice setup.
 
So I thought I was going to run holly pump to filter to regulator set probably around 7 1/2 psi then up to carb and no return s all in AN6 But now listening to you guys majority of you are suggesting running AN8 and use a return so I will get some AN8
And should I still go with the blue pump if so can I still regulated on the return
 
You have the -6 so there is the return line. -8 for the feed. Since you may second guess yourself on it get it over with. It won't hurt anything (except the checkbook.)

Wish I had run a return line on my last hotrod. Some of the problems I had with fuel would have been corrected....

JW
 
With my BG400 pumps I run a return from the fuel pump in back of the car and dump into the top of my fuel cell. I built a tube so the fuel enters under the fuel near the bottom so it doesn’t make bubbles.
 
This is going on a street car, 340 small cam, headers,
If it was a drag car I would run 3 separate lines from a block.

IMG_5854.JPG


IMG_5869.JPG
 
F21 said:
So I thought I was going to run holly pump to filter to regulator set probably around 7 1/2 psi then up to carb and no return s all in AN6 But now listening to you guys majority of you are suggesting running AN8 and use a return so I will get some AN8
And should I still go with the blue pump if so can I still regulated on the return
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Just make certain to get a return style regulator. There is a difference.
 
I ran a blue Holley pump with 6an from cell to reg to carb on my sb stroker. It worked ok. The pump was so loud I couldn’t stand it! So I got a quick fuel 230 pump and return reg. I run 8an from cell to reg and to carb. Plus quick fuel filters. 10an return to cell. That’s what they recommend. Works great no issues. Pump is 10 times quieter! 410 stroker ported w2’s solid roller, and I street it.
 
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