Truck details: SBC 350/th350, edelbrock carb, big solid roller cam.
Drove it Friday night, it was fine. Drove it 100 miles saturday, it was fine. Saturday evening I pulled the valve cover to change the gaskets to thick rubber gaskets only to realize I need long bolts to run them, so put the older rubber gaskets back on. Then I changed my oil yesterday (Valvoline 10w30 and Lucas oil treatment). Took it out last night for a drive, and under WOT it's sputtering from about 3k-4k rpm. Driving it under normal conditions (even and slow on throttle), it runs fine all the way to 5k. Sputters once it gets up in RPM from a stop as well. I spilled some oil when filling it back up, so was thinking maybe the #8 plug/wire got wet. Pulled the wire and the plug and seemed fine. Put it back on and drove it to work this AM, and it's doing the same thing. Coincidence that this didn't start until the oil was changed? Runs great until the pedal is mashed, idles great, etc. So after searching I see this could be a number of different problems.
Edit: Seems to be a common problem with the 1406 edelbrock carbs. Am I off base here? I'm thinking either ignition issue, or fuel delivery issue?