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Discussion Starter · #1 ·
I'm finishing up the swap on my 56 from 6 cyl to 350 ci V8. I have read that due to heat from dual exhaust, I will need to change the original fuel line from the 6 cyl which is routed on the inside of the frame rail to the V8 on the outside of the frame rail on the passenger side. Same is suggested for the brake line. Anyone out there who didn't find this necessary or had problems with the fuel supply if they didn't. Anyone care to comment? Thanks,
call me almost done!
Don
 

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I could see where that would be a problem, but it hasn't been a problem on my car. My car was originally a 6-cylinder and I left the fuel lines on the inside of the frame as well as the brake lines. I haven't had a problem yet. May depend on your fuel demand too. I believe that the V-8 cars also had a larger fuel line to supply the motor (maybe not though) and I've heard that the 6-cyl fuel lines are not large enough to accomodate a radical motor. I'm fine in that area with my car too.

--Jeff
 

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I think the fuel line is about the same unless it was a powerpack or fuelie car as far as size go. I ran my 57 with the stock line, inside the frame with duals and had no problems.
Terry
 

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Discussion Starter · #4 ·
Thanks guys! I already ordered the new fuel line, brake line and clip set, but I won't rush to change them now!

Don
 

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From what I've read in the manual and other sources: Standard fuel line is 5/16 and will support the 6 cyl. and single 4 barrel V8. For dual carbs the fule line is 3/8 and is run outside of the frame. There was something about dual exhaust, though I do not have that material in front of me as I'm at work.

I'm in the process of changing from a 6 to an 8, with full length headers, and while I'm only running a single 750, since I'm installing a new gas tank, I'm using the 3/8" line -- both it and the brake lne will be run outside of the frame.

Biggest reason: The heat from the exhaust can boil the brake fluid and you lose your brakes. Happened to me once in an overloaded truck. The header developed a crack -- heated the brake fluid to boiling. I came around the corner of a two lane road, slightly below the posted speed limit, the road was blocked due to an accident -- hit the brakes -- pedal went to the floor. Managed to get the truck into the ditch clearly the cop, the cars and not rolling my truck. Funny thing was after I finally got the thing stopped the "Brake Fail" light came on.
 
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I'm finishing up the swap on my 56 from 6 cyl to 350 ci V8. I have read that due to heat from dual exhaust, I will need to change the original fuel line from the 6 cyl which is routed on the inside of the frame rail to the V8 on the outside of the frame rail on the passenger side. Same is suggested for the brake line. Anyone out there who didn't find this necessary or had problems with the fuel supply if they didn't. Anyone care to comment? Thanks,
call me almost done!
Don
Hi wraplock:
I have e-mailed a tech article on fuel and brake line installation for dual exhaust cars, hope it helps.
Bob
 

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I ran mine on the outside only because I was replacing everything and went with fuel injection. I had to have a 3/8ths supply and 5/16" return. I also routed my brake line on the outside on the drivers side. Didn't make sense it being on the right rail and the master cylinder being on the left.
 

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The fuel line is a must and on the outboard of the RT side. The brakes can stay inside. Any one putting in brake system new should think about Silicone fulid, been running it in my 57 for over 20 years. I have 4 wheel dlisks and never had a problem, also don't have to worry about the paint!!!
 

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The fuel line is a must and on the outboard of the RT side. The brakes can stay inside. Any one putting in brake system new should think about Silicone fulid, been running it in my 57 for over 20 years. I have 4 wheel dlisks and never had a problem, also don't have to worry about the paint!!!
kzo57, why do you think it's a must to go outside the frame? I'm trying to decide which way to go with mine and I haven't heard anyone say not to go inside the frame rail yet. Staying inside would sure simplify my tube bending.

I thought there were some problems with silicone brake fluid. One is that silicone is mor compressible, leading to a spongier pedal. Here's some others:

http://www.adlersantiqueautos.com/articles/brake1.html
http://www.adlersantiqueautos.com/articles/brake2.html

Silicone, when sucked through a leaking vacuum booster into an engine, burns to form silica sand and quickly wears down an engine's internal parts. Glycol burns harmlessly.
Silicone affects rubber brake components' “elastomers” differently than glycol and may not be compatible.
Silicone will not mix with water; glycol will.
Silicone will not lift paint; glycol will.
Silicone contamination in your shop will cause fisheyes in future paint jobs; glycol will not.

"If silicone is introduced into an older brake system, the silicone will latch unto the sludge generated by gradual component deterioration and create a gelatin like goop which will attract more crud and eventually plug up metering orifices or cause pistons to stick. If you have already changed to DOT 5, don't compound your initial mistake and change back. Silicone is very tenacious stuff and you will never get it all out of your system. Just change the fluid regularly. "

http://www.superchevy.com/technical/chassis/brakes/0509sc_fluid/

SILICONE BASE BRAKE FLUID (SBBF)
The U.S. DOT defines silicone brake fluid as that which consists of no less than 70 percent of adiorgano polysiloxane by weight. Silicone-based fluids are regarded as DOT 5 fluids. They are highly compressible and can give the driver the feeling of a spongy pedal. The higher the brake system temperature, the more the compressibility of the fluid--increasing the feeling of a spongy pedal. Silicone-based fluids are non-hydroscopic, meaning that they will not absorb or mix with water. When water is present in the brake system, it will create a water/fluid/water/fluid situation. Because water boils at approximately 212 degrees F, the ability of the brake system to operate correctly decreases, and the steam created from boiling water adds air to the system. It is important to remember that water may be present in any brake system. Therefore, silicone brake fluid lacks the ability to deal with moisture and will dramatically decrease a brake systems performance. Silicone brake fluid has a number of strengths and drawbacks.


Strengths:

1) It has a high boiling point since it does not absorb water. Therefore, there's no so-called wet boiling point.

2) Doesn't absorb moisture.


3) Doesn't remove paint.


4) The viscosity is more stable over the extremes of temperature.


5) With the exception of some formulations used in external boots, silicone brake fluid is compatible with all standard brake components.



Drawbacks:
1) It's hard to pour without entraining air bubbles--hence an application will generally have a softer, spongier pedal feel.

2) It doesn't absorb water, so any water already in the system accu-mulates in the lowest point of the system and stays there, causing rust.


3) Glycol fluids begin to compress near their boiling points, whereas silicone fluids begin to compress at around 300-350 degrees Fahrenheit.


4) Additives in the fluid can vaporize at comparatively moderate temperature, increasing the spongy feel.


5) Silicone fluids expand significantly when hot.


6) Silicone fluid is functionally incompatible with systems that have held glycol-based fluids for any length of time, requiring flushing and seal replacement (there are counter opinions on this, which state that the modern silicone formulations are in fact compatible with only a flushing, rather than a complete reseal). The actual DOT specification requires chemical compatibility, so as far as that goes, the two fluids won't cause reactions if used in the same system, but they certainly won't mix, either.


7) It's pretty much incompatible with anti-lock brakes because the silicone fluids tend to be more viscous, which can cause problems with the timing of the pulses that are intended to work with the thinner glycol-base fluid. This sometimes leads to damage of the ABS valving. The rapid pulsing necessary to anti-lock functions tend to cavitate the fluid, as the tiny bubbles collapse and coalesce into larger ones, and then collapse and reform into smaller ones. This tends to counteract the ABS effect and can diminish the actual effective braking. This condition also heats the fluid and can lead to even more sponginess and possible damage to the ABS controller. Thirdly, silicone brake fluid tends to foam when expressed from a small orifice under pressure, reducing its hydraulic effectiveness greatly."
 
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