Fixed the issues that were causing the engine to cut out after X number of minutes. First I went through the carb and found that there are two different float settings depending on which needle you have and use. I found on Mike's Carburators website that for the spring needle you set it at 9/32nd's and for the solid needle you set it at 15/32nd's. I reassembled the carb and ran the engine. No signs of flooding but, it still died after 15 mins! I walked away and scratched my head for a while. I remembered that when I had my old distributor w/pertronix installed that it would idle long past 15-20mins, just performed poorly and wasn't firing the #6 cylinder under compression. That was why I installed the Langdon's HEI. So, I thought something must be wrong with the HEI unit or the coil that goes with it. (He sells a Ford 300 I6 coil to pair with the HEI) I decided to borrow the coil from my 1978 Ford 300 as I new it had been running and was a good unit. I installed it on my 58' and started it. It ran for over 45 mins till I turned it off. I have since driven it several miles with no issue. I have never seen a coil act in that manner. I have only had them fail when over heating and then not restart for several minutes until cooled.
So, to summarize: My carb float was not set correctly since the rebuild kits mention only one setting. And, my ignition coil was going bad causing it to die at random intervals. Just got back from getting the truck inspected, so finally I can get it registered after 6+ years of sitting and have her street legal! Thank you all for the thoughts, advice and directions. It helped immensely in tracking down problems!
