Have fresh rebuilt 8BA in my '36, pored in 4 gals. of distilled water yesterday, poured in 5th gallon today and water dripped out of header where it connects to header extension. Cracked block? Didn't have this problem on test stand. WHOOPS, upon closer inspection I see the leak is originating from head bolt under thermostat housing on right side. Maybe BARR'S STOP LEAK will solve the problem?
Oh man don't use barrs, that stuff is no good and just junks up the system. Pull the head and check what's going on then re torque and check again.
Fix it the right way. Pull the head off and inspect everything and make an educated decision from there. Barrs leaks should only be used to get you home from somewhere youre stuck with no other options. All of those "miracle" motor fixers are just garbage bandaids. Youve got a nice motor and a nice car. Take care of its heart.
I use this or something similar on any bolt that p***es through a water jacket. I have a can of Permatex aviation sealer I've used for a long time. Bob