I had a heck of a time figuring what was going on Why it would run rough when it got Op/TP . With the wire from the relay and the OE wire hooked up it runs great even when warm. It gets 13. volts at coil.I saw a couple of videos of people that got the volts from accessories.

After several days I think I have come up with good fix. I installed a 12 volt wire to the coil using a relay. Pentronix recommends this. I also ramped up the initial timing to 18. I have driven it and am convinced this will do the trick. Im still gonna play with the timing to find the sweet spot. I appreciate the advise.

I have a recent new rebuilt 390. The engine starts fine when cold but as soon as it gets to operating temp it runs rough and wants to die. Ive had a holley and an Edlebrock carb with same results. Does any one have  any ideals.

The holley 750 is new and tuned good,new  filter, pump,and hei dist, , tank is clean and line is clear, I was having this problem last year someone told me to replace the fuel cap with a vented one and boom it seem to work. didnt have the problem for 6 months. Then last week it happen twice.. I notice that the cap when taking it off it is under alot of pressure. Is this normal.

I have a 390 in my truck. Im trying to figure out why my truck stalls at hywy speed around 55.I can usually restart after a few.   I replaced most of the normal things like pump, filter, rerouted fuel line, I replaced the fuel cap with a vented one and it seems like it fixed it for awhile.Then last week it stalled twice. No Im really baffled.Does anyone have any ideals.