Valve springs help

You guys must be getting sick of me. OK, here is my newest dumb question. I just pulled my intake as it had an oil leak so I'm already halfway there. This car has changed hands several times but I tracked down the guy who bought it from the guy who built the motor. I can no longer get ahold of him but he did say way back in the day the dart did run around 12 flat. He also said it was a huge cam and thought it was a 509 purple shaft. He said the builder told him to change the valve springs if he was going to drive it on the street as they were heavy and would wipe the cam. Here is what I know for sure, the car runs very well, Its a hydraulic cam that is purple between the lobes, the valve springs are double springs with dampers between them. I know you can change the springs with the heads on but have heard its a pain. I can try and take some pictures if it helps. My questions are:

1) Is the 509 the largest hydraulic cam?

2) Should I change the springs now that I'm this far into the motor?

3) What should I put in for springs on a mostly street but odd weekend track car?

4) Is it possible to tell what the cam is for sure without pulling it out?

Thanks a ton

I know I ask a lot of engine questions and am a pain in the arse.

Dave
Author: admin