Is it necessary to run rubber fuel line from the cab to the frame?
 

It seems to me that with poly cab mounts, the cab's not going to be moving much. Can I do steel all the way from the tank, or is this a big no-no?

Re: Is it necessary to run rubber fuel line from the cab to the frame?
 

Sure you could. But I would use a short section (6" - 8") of rubber or braided stainless between the steel line and the fuel rail. I would think there needs to be a little something there to take up any twist and vibration, like an OEM setup is.

I don't remember if you are using the stock in-cab tank, and something in the rear. Does the in-cab tank have a threaded fitting on the fuel line into the sending unit?

Re: Is it necessary to run rubber fuel line from the cab to the frame?
 

It's the in-cab stock tank -- The out line already has a -6AN male fitting on it. I'm getting ready to pull the sending unit out, and plumb in a -6AN bulkhead fitting for a return, but I'm thinking about just welding a piece of steel line into the sending unit because I don't see how those bulkhead fittings would make a good seal.

My pre-filter, pump, and 'vette style filter/regulator is already mounted to the frame, just need to run lines to everything.

I was planning on steel all the way from the sending unit to the firewall and running a short piece of braided to the fuel rail.

But somewhere along the line, I remember seeing that the stock setup uses a short piece of rubber from the cab floor to the frame rail hard line in the even that the cab twists or moves/whatever...

Re: Is it necessary to run rubber fuel line from the cab to the frame?
 

I've seen this done before and should work just fine.

Now that you mention it, I think I do remember my 68 being that way when I pulled then tank out. Although, it's really not a huge expense for the piece of mind to install a couple AN fittings and a short piece of braided hose there. But I follow your thinking; new mounts, should be little to no twist. But, in the future after you have a few miles on it........

Re: Is it necessary to run rubber fuel line from the cab to the frame?
 

:lol: yeah, but now my time-frame will be set-back another week as I wait for 2 more -6AN male hardline adapters--- Maybe I'll just do rubber all the way from the sending unit to the pre-filter, and from the return up to the tank ?
This would kind of defeat the purpose of me trying to not use ANY rubber line (except at the fuel rail...)

Re: Is it necessary to run rubber fuel line from the cab to the frame?
 

Thinking out loud here.......Basically, you could use just enough rubber as needed for connections to the steel on the suction side of the pump, but I would stay with steel or braided hose on the delivery side of the pump. On the rubber to steel connections, just flare the end of the steel line, and use FI rated clamps.

Plus, Summit will have you parts in 2 days or less. :D

Re: Is it necessary to run rubber fuel line from the cab to the frame?
 

I guess what I am trying to say, in my seemingly endless random babbling :lol:, is that I want some rubber is various parts of the system to absorb normal road vibrations. As a retired firefighter of 14 years, I can say for certain you don't want the steel line to stress and start leaking. Murphy ALWAYS makes them spring a leak near heat or spark! :lol:

Re: Is it necessary to run rubber fuel line from the cab to the frame?
 

I would get a piece of braided line made to go between the cab and frame and another piece between the frame and engine. Even with poly mounts there will be some movement that will eventually stress the lines. I would hit a junkyard and try to find some of the 18 or so inch pieces that factory uses on modern stuff.

Re: Is it necessary to run rubber fuel line from the cab to the frame?
 

Darn it :D

Oh well, I'm sure there was something else I wanted to order from them anyway, like mufflers (ultraflows!)

Time to start another shopping list. I guess I'll only be needing about 8 ft. of the 35' of steel line I got :lol:

Thanks guys.

Re: Is it necessary to run rubber fuel line from the cab to the frame?
 

Ok, so now I feel like I'm going in circles... My main goal was to minimize rubber, but it seems like I'll be using a lot more than I wanted to.

Rubber from the bottom of the cab over to the pre-filter, then between both filters, and the pump, that takes up about 18", then I have maybe a foot or so before I'm up to the bottom of the firewall. BUT!!! -- I'll be transisioning away from the frame, and should be using rubber again.

What do I do? Just terminate the steel with another -6AN male fitting where the frame and firewall kind of line up, and run rubber all the way up to the fuel rail?

I thought running some fuel line would be one of the easier things I had to do.

Here are some pictures so you can come up with a good way for me to do this. :lol: You can see the rotted-up gromet in the floor where I'll be coming down with steel, making a 90 over towards the pre-filter, and terminating so I can use a piece of rubber there.