Wellallrightythen, I re-read the entire post... I wouldn't worry about the cracks in the logs that you posted a picture of. You're exhaust outlet location with your snails is fine. Your exhaust outlets are fine. If you blew the head gaskets there's no way for you to measure the amount of oil vs. water in the pan, it's going to look like a mess no matter how much water got in there from a blown head gasket or two. If it were mine, I'd run the current exhaust logs and snails.

Put a 3 inch piece of hose with a bolt shoved in it and clamped with a couple of hose clamps on one of the tubes on the log, on the other tube you can cut off an inner tube where the air valve is and hold it on with a hose clamp. You don't need 110 psi to check it, maybe 10 lbs...