Nope, pressurized the cooling system and it lost 1/2 psi overnight. With the valve cover off, looking through the opening in the head that goes to the lifter valley, I can actually see a drop form and roll down about every 5 seconds. I had to sleeve #3 cylinder 17 years ago for a pinhole as well. But this one is on the valley side, not in the cylinder. I'm not taking another chance. When i bought the car, it had sat with water in the cooling system for about 10 years so there was a lot of scaled rust.
I am pulling it to tear it down to check everything else but if I only need the block then I guess any 318 from '67 - late '80's will work, right?