Need some advice

I am looking into a buying a Mopar 360 (71) with J heads ( Large Intake Ones ) New Mopar Purple Cam .450 Lift and new springs, i was wondering if $600.00 is asking to much for it. I need a motor and was wondering if this is a good price. What other question should I ask the motor guy about the motor, he is going to call me back soon and talk more about it.

Thanks