i have a mild 454 and was thinking about going to just an electric fan instead the the mechinal one , i have a large alum rad and going down the hiway it runs 170 degrees so i think it's large enough . how many cfm electric fan do you think i would need

Good rule of thumb is buy the biggest one you can afford, keep in mind the amp draw though..

i was thinking of getting one from summitt they have a 3000 cfm fan for 95 dollars it draws 7.5 amps