Are the cooling systems on these cars too small for a mildly built 355? This is an 85 that had a tpi 305 we didn't get the electic fan with the car but now have 2 14 inch fans on it and still can't go more than 5 miles without getting to 240 degrees

 

if the fans aren't shrouded, they wont be very effective. Is it a carb or FI car? under or over advanced timing will cause overheating too, check your hoses and that your fans are coming on when the should. These cars from the factory had the fans wired to come on at 220ish....way too hot!

 

It's the tpi with 24 lbs injectors and a reprogrammed computer and cam to match , we will recheck the timing tonight, I'm not having much luck finding shrouded fans and also wondering about a radiator with more cores . The older pickups used to have a four core when running a big block , certainly there has to be something for these cars

 

You should be fine, I'm running a mild 355 with a stock rad and a single electric fan and I never get over 180.
If you're using the factory gauge, that could be the problem.
They can be horribly inaccurate. As in, hooked up aftermarket and factory gauge to the same sensor, aftermarket read 180, factory read 230-260.

 

so last night we checked the and its way off , checked the engine light codes and it said has a short in the cooling sensor wire so we're thinking its trying to retard the timing because it thinks its hot , i've got it advanced to make it run and that is actually making it hot! computers!!! We're running a mechanical guage for the temp cause the dash guage is peged out , is there a seperate circut for the guage and the computer reading or do they use the same one for the guage and the computer imput?

 

ECM gets it's reading from the sensor on the intake by the thermostat housing. The one on the drivers side head is just for the gauge. Probably melted the wire against the exhaust and is grounded.

 

The stock cooling system can handle a 355 no problem.

Get a stock or taurus fan setup. Also make sure your air damn in in place

 

Agreed. The radiator should handle it but the stock fan(s) are junk IMO. A Tuarus fan is 3X the fan the stock one is in terms of air flow! I use a Volvo relay for mine like so:

 

I have a 355 in my 84 with a single electric fan and except for when the AC is on, It stays cool just fine.