I have a 92 350 tpi with cast iron heads, been building this car for 2 years finally got it on the road and during the shake down run looked in the rear view and saw the worst thing ever, smoke billowing from out of the back of the car. when I got the hood up the dip stick was pushed out and oil every where. found there was water in the oil. once we got it down to the shop. checked the oil adapter, and pressure tested the cooling system. it seems to be holding pressure, but looses about a half pound per hour. any suggestions. also car still runs great, suggesting the head gasket isint blown

 

if its coming out the tail pipes, the water is getting into the cylinders. It could be a intake manifold gasket, but would seem to be a head gasket or crack in the head or block.

 

No water out the pipes, it fills the oil pan when hot

 

Did you use thread sealant on the head bolts? Look under the valve covers for signs of water. Improper sealing around the water passages at the intake manifold could also cause a weak leak that gets stronger as things expand, also double check the torque on the intake manifold bolts. You say you've been building the engine for a while, did it get a bore job? It's possible the cylinder water jacket cracked near the bottom of the cylinder, just below the rings while being machined.

 

problem solved, after pressurizing the cooling system overnight and then pulling every spark plug, found that there was no water in the cylinders. took the intake off and the rear water ports on the head were leaking. replaced the intake gaskets and all is good. apparently this is a common problem. hope this might help someone. have a great day!!

 

Good job! Dont forget to change that oil lol.