not to hyjack but I plan on putting a .507/.510 cam in my 340 with X heads. I have'nt measured anything yet but I'm wondering if i'm gonna have to do some extra machine work.
stock rockers...are not 1.5...probably close to 1.4...and you are going to lose another .010 lift due to the back pushrod angle in sb mopar..but if it was my engine I would check the clearance before I started the engine....