tufcj
I can send you a full set of 16 used factory rockers, studs, balls, and nuts for the cost of shipping. I have 291C heads on each of my 69 390s. I use 3/8" small block Chevy studs (ARP), Crane Gold rockers with cool nuts, and .100" longer than stock pushrods. This has worked well for me with valve lift up to almost .550". Any more lift, I would move up to 7/16 studs and matching rockers. The valve guides do need to be machined for positive seals once the lift exceeds .500".
I'm sure I could get a set in a small USPS flat rate box for $7.15 shipping. Let me know if interested.
Bob
tufcj