I have loosely followed your other thread.

I know you mentioned a coupled different hoses between the tank and the hard line going up to the mechanical pump? I would be very susbitious of a leak there or blockage. It don't take much on the suction side of a pump, it may not leak fluid but it can suck air.

Then maybe try a reg airtex pump? I run them and have had good luck with them.

Here's a option for a return line.

I use a hemi vapor separator bolted to the fuel pump with a #57 orifice in the return line. Been this way since about 2003 and have driven the car hard at hi altitudes and very hi temperatures at hi altitudes and it has never let me down. Non of my stock fuel line was insulated. I drove it wide open for like 5 or more miles at a time out in Bonneville on the salt on a 95 degree days, 3 different years and it never ran out of fuel. Do you know how hard it is to drive 120 MPH for like 5 miles at a time?

Anyway here's pictures of my junk.
I included a picture of my gas tank connections, simple and sweet, not much chance of sucking air here.

If your car model ever came with a hemi, then you can order a pre bent 1/4" return line. Even if your car didn't come with a hemi I would call fine lines and ask them to bend up one for you in 1/4" just like your suction line and it will fit fine I'm betting.




Couple water pump bolts came loose and caused the rust stains. I haven't taken the time yet to pressure wash it off in this photo. Quality Tawan dipstick, no china crap on this motor. lol

I took it to Vegas last July, it was 110° pretty much 24/7. I idled it around for over a hour at time 3 times until I got smart and did my cruising at 6am so at least I could motor around with less traffic. One of many examples of extreme service is all I'm saying. Stock ain't always bad. Good thing my black car has AC otherwise it would be unbearable.
6AM the Vegas "strip" It was all mine, kinda.