Reply to "Pushrod diameter - 393cui"

I happen to like Smith Brothers or Manton custom pushrods, who also sell a cheap adjustable pushrod to find what length you really need; stock length normally is wrong. Custom-length pushrods also come in a bewildering variety of wall thicknesses that assist in stiffness. Garden-variety street engines usually get 0.065" or 0.080" wall 5/16" pushrods. But they also are available in 0.120" or even 0.160" walls.
There will be fitment issues in a host of places with oversized pushrods. For those concerned, weight of the pushrod and lifter has proven to be much less important to valve float levels than extra weight on the valve side of the rocker arm. I would suggest sticking to the cam grinder's recommendations for your spring strengths. They know their product better than we do.