427 S/O Perry I am not trying to unset you or say I am a expert in the FE field. After breaking rockers and shafts in my car over the last 10 years, I am just trying to give you the best info and solution so you will not have this problem in the future.
If the lifter comes out of the bore like in my car 3 years ago the only thing that saved the motor was the 3 quart accusump
oil tank. I only had 15psi in the motor on a cool down lap and went 1.25 miles with low pressure.
You motor is worth 7-15K dollars. I don't think you would be very happy to get a bill for 6-8 grand for a rebuild over a rocker breaking in the motor. It's just info to help you, You can take it or leave it. There was no intent to pi$$ you off. Other guys have gone down the same road as you, had the same problem and are offering the same advice. That's all. Have a good one and good luck with the repair.
Rick L.