[sunman]

The 1973 390 in my bus was rebuilt 35 years and had about 10K miles put on it than was parked in front of restaurants for 25 years
I just pulled the heads, (C4AE-6090s !!) , the cylinders look great, the pistons move sideways in the bore and show no signs of rings being stuck
The valves look new and are tight in the new guides
The rubber umbrella valve stem seals are loose and hard as rocks
It’s a clean up and new gaskets
With only 10K on your motor maybe you have the same thing going on