Help with building a bit more power in to the 318

pressurize the cooling system and pull the plugs.
Roll the motor over by hand while the coolant system is presurized.
you might be able to see if it's a certain cylinder is filling up with coolant or if it's a block leak by the crank case filling up with coolant.
Drain the oil and keep the plug out.
This is good info. to have before a tear down.
It might just be a blown head gasket.
As far as 400 horse out of a 318, it's a very good concept, but if you dont have the drive train combo to back it up, it will be a dog.
LIKE \NO GEAR\LOW STALL CONVERTOR=SLOW.
A 400 HORSE 318 WANTS GEAR AND A HIGH STALL CONVERTOR AND A LIGHT WEIGHT CAR.
good luck :tongue3::coffee2: