Well,  thank goodness,  I've found the problem.   First of all,  I have rebuilt the supply pump.  Every time I used the primer,  it would leak fuel.  I figured that it had to be taking in air at the same time.  But that did not cure the starting problem.  After that,  I took into consideraion that the fuel tanks were not of Mack origin...(they are freightliner tanks)...with the help of a couple of good mechanics at my place of work we came to the conclusion that my Mack needed a check ball installed between the tank and the primary filter to assist in holding pressure.  So far,  I've let it sit for 48 hours and she started after a few revolutions!!   Thanks for everybodys' input...I'll post a pic as soon as I figure put how...I'm not much of a computer guru....