Hehe, sorry man, but you aren't gonna want to hear this, but I think it may be your rings are bad. I am not sure exactly what all was done to your FE, but I do know JayB had it. I AM NOT blaming this on JayB, this exact same thing happened to me. The company he used to hone my block and paint it and assemble the bottom end did a sh*t-*ss job on mine. The gap on my rings was not measureable with the right tool (sorry, I am having a brain fart at the moment or something), I could measure it with a ruler. It was about 1/8" on half of my rings. Which caused me to crack two of them and my oil pump to go bad. The company was called Revmasters, and I guarantee you they will never ever get any business from me again.
I am not saying this is your problem, but it is a good possibility if he had them do it. I don't know what all was done to yours. I think you mentioned b4 that you had new pistons/rings in it, which would mean it needed to be honed and assembled. If you want I can ask him next time I see him who did yours? I should see or be able to get the message to him today, so I will and I'll just let you know.