Get in the car start it up put it in gear hold the brake on and floor the throttle. See what the highest rpm the tach goes to. This is the easiest thing to check you don't even have to open the hood. If it doesn't go to 2500 even with a bad tune you need a higher stall converter. A good running small block should stall at no less then 2800 with a stock 340 converter. Truck or mild passenger car converters will kill a performance car. I took a 340 trans out of a dart and installed a trans from a small block fury years ago. It was like someone poured the trunk full of concrete . It was a real dog. I switched out the converter and the car was back to performing the way it was when purchased new. Try it what do you have to lose except a little time and fuel.
yeah baby....The engine combo is very similar to hers. 
