That Edelbrock 1.55" spring has a seat load of 140lb at 1.880 installed height and a spring rate of 354 lb/in. For a .509 cam it'd have 320lb over the nose. Coil bind is 1.160" It appears to have enough margin for close to 0.700" lift.

Is it too much for a hydraulic flat tappet cam?

R.