Thermostat host leaks
 

Hello i have 1967 plymouth fury 3 and just replaced new radiator, water pump and thermostat. when i put it back on it started leaking from the host. I'm not sure if its from the host or the gasket. Please help

how old are the hoses and did you use a silicone gaket sealant on the thrmostat housing?

Yes i did and i just bought aftermarket thermostat hose, gasket and new thermostat. I dont know why its leaking. So after i drove just tonight, my tranny leaking from the radiator. My car's a fact 67 year model.

check and make sure your themostat housing is tightend down and also make sure your calmps are tightend down as well. if they are just snug they will leak

Are you using good screw type clamps? If the thermostat is leaking from the gasket ? the housing may be corroded.
Make sure you are installing it correctly engine/gasket/thermostat/housing along with a dab of sealer on the bolts also
I do not like to use silicon on gaskets , I use gasket cinch/permatex from a brush on can