after dropping a 350 into my car and having it run, It is running a hot, and If it turns out to be one of the heads, Would I be able to easily put on a pair of 305 heads and drive with those on for a bit until I save up enough cash to buy better 350 heads?

 

is the motor bored over? What kinda compression are you running? 305 heads (atleast of a 3rd gen) will only skyrocket your compression and give not only more heat but lots of other problems. 305 heads are 58cc off these cars and most 350 heads are between 64cc and 78cc .

 

Yes you can use 305 heads on your 350.
The compression ratio will be higher, but will not likely be exessive. How high depends on what head you are replaceing, what pistons u have etc.

Stock 305 heads have smaller 1.84" intake valves but the motor will run fine.

 

Not sure on compression, its waiting for me to get to It, and my main concern is just getting it down here so I can work on it. If it runs much hot'er just offset it with a cool'er thermastat? maybe a 170?