I recently upgraded the Car and intake on my 66 GP.  I went with an Edelbrock 600 on a stock 389.  I installed a new transparent fuel filter from NAPA before the carb.  When the car is cold the filter stays full of fuel and the pump seems to be doing its job.  When the car heats up the ammount of fuel in the filter drops considerably.  Sometimes it appears as though there is noting in it and the fuel entering is inconsistent.  I thought that the problem might be the fuel pump.  I replaced the pump and the lines thinking I might have a leak somewhere.  I re-routed the lines from the original stock location on the engine block to a cooler location with less of an incline and it is still doing the same thing.  Is it normal for the fuel filter not to stay filled with fuel?  I am a novice at restoration and I am trying to teach myself how to do all of this.  Thanks for the input I know this is like my 4th Post.  

I remember having the same happen to me. It never caused any problems so I left it alone. Check your fuel pressure after the filter. If it's good and the car drives ok don't worry about it. I believe when the fuel warms up it releases some of the oxygen in the fuel. But I am just guessing.  

The fuel pressure seems fine when the vehicle is cool.  As the temperature increases the pressure becomes a little erratic.  If I turn it off when it is hot and try to re-start, it has a bit of trouble until the filter gets some fuel in it.  As long as I keep it running it is fine.  I followed the lines all the way to the tank and the only places I can see where it is picking up heat is right after the gas tank and by the pump.  When the tail pipe curves over the rear axle it is about 6" away from the steel gas line.  The fuel pump is located in front of the P/S pump and it runs along the engine for about 8".  There are no heat shields any where along the line.  Do you think it would be a good idea to re-route them away from the exhaust and P/S pump?  

Yes. The cooler the fuel the better.  

Gas is not the same chemically as it was in 1966. This is particuarly true if you have ethanol added in your area like we do here in NV.

I have found that gas will completely evaporate out the carb after about 1 week of sitting.  Who knows what's happening in between???

The only solution is to add a pulse-type inline fuel pump.  Do NOT add a rotary vane type fuel pump (Carter) because your mechanical fuel pump cannot suck through one of those, only a pulse type.  NAPA amongst others have them and they are relatively inexpensive.

Craig  

Thank you.  The gas here is FL is mainly running a 10% ethanol mix.  I went ahead and removed the insulation from under the hood to try to lower the temp and moved the fuel line further from the block.  It appears to have helped a bit.  I am going to order the pump today. I appreciate the help.  

You're good to go. The pulse type fuel pump is the answer. I have one on every one of my NV cars.  

Craig