I removed the 305 eng. and installed a 350 when i run my a/c the temp will continue to rise to the point of overheating,i installed a new radiator,160 thermostat new radiator cap my cooling fan is on when a/c on,when i bought the car the electric fan did not have a shroud. is it supposed to?will a 305 radiator cool a 350 properly.And my lower air dam is in good shape.on highway it is ok city driving is were i have trouble.without the a/c on the car is fine.

 

Sounds like you need a fan shroud. In my experience the stock radiator for the 305 is a damn good radiator. Except for the plastic side tanks

 

They didnt come with a shroud, shouldnt need one. It may be the fan motor is weak and its not spinning at full speed. Does the fan stay on with the AC on? It should.

 

fan was not coming on so i hard wired it to a switch the gauge wire i used was smaller diameter i proably need larger wire.
and i did install new motor.

 

I run 20A wiring and i havent had a problem with it, you should wire a relay in there or you will be replacing that switch every fue weeks.

Once i get home i will have a look at my old fan and see what mods that can easly be done to improve the way it works.

UPDATED:
Ok i had a quick look at my old fan and i recon you could silicone some 15mm or 9/16" maby bigger round (thin wall) hose around the side edges of the fan housing closing the gap betwene the fan and the radiator.
that way you are making the fan pull more air through the radiator not from either side of the fan.

This is only a temp fix, You could make a small shroud up if you wanted to do it properly.

 

I will try a larger dia. wire,i was burning up switchs until i installed a 50amp switch.may need a relay.