What valve springs are you using that's good for around a .520 lift and fits in the stock OE pocket (no machining) for my 93 5.0 HO? I called CJ ponies and the rep gave me pt#986-16 which I think is Compcams #. He stated it does not require machining of the stock head spring pockets but their description reads some machining required. He also asked me if it was a 289. Maybe he didn't hear the year model.

 

springs should not be picked based on lift alone........ramp rates and cam profile all factor into it.......reference what the cam manufactorer recommends for the profile