hey i just bought my first mustang it is a rebuilt 5.0 the guy i bought it from made it into a 347 stroker cars runs great it just overheats, the motor has roller rockers an agressive cam shorty header but only has the stock intake manifold and fuel system.....

back to the overheating i changed the thermistat, (didn't help) i check the oil and there was no foam in it so i dont think it is the head gasket. i flushed the system and put new antifreeze in it still no change changed the both temp senors to the fan and the gauge still with no change. the only think i havnt done is change the stock radiator to a better one

what do you guys think?

 

Overheating symptoms tell alot about what is failing. You need to be more specific about when it's failing, when it's not, and if it overcomes it during any phase of driving.

Secondly, you could be chasing a huge lean issue. That setup is surely running dangerously lean, and lean = heat.

 

are you sure the radiator is not partially plugged up. Run it till it gets up to temp and then feel around the surface of the radiator for any areas that seem like its cooler than the rest. If you a have a large area that feels cooler then its likely that the radiator is full of corrosion . Also run it with the cap off up to temp and when the thermostat opens you should see the coolant circulating really good inside the cap, if not either the radiator is plugged or the water pump is weak.

 

it steadily builds heat over time and once it gets to the red mark there is nothing that i can do to cool it down except shut it down

also I'm almost sure that its running lean because the engines fuel system hasn't been change, its stock

 

When does it overheat?? sitting still?? driving down the road?? be more specific...also is the belt routing correct??

 

Check the radiator for proper flow.

 

overheats while driving

 

have you tried a new cap?