318 exhaust manifold bolts and nuts....

ive had to weld nuts to a couple of mine, one in my big block and one in my 318 in my powerwagon. the smallblock was a bear to get to seal up, i tried pipe dope, teflon tape, rtv, shellac, threadlock, anaerobic gasket maker, no2 rtv, it all failed. i ended up using a stud extractor and some teflon goo pipe dope and reefed the stud in the hole about as hard as i wanted to go, luckily it sealed, finally. then it ate the heads (exhaust valves and seats burned up, non hardened, 73 build)....so now new heads with hardened seats, new studs and pipe goo, no more issues! if you ever have one thats seeping bad enough get it fixed asap, the coolant can leak into the exhaust ports, pool on top of the valve or in the cylinder, and ruin them. ive seen it happen before. not cool.