Before you invest any time and costly valvetrain parts make sure every intake, exhaust and accessory bolt hole is located exactly where they are supposed to be. Once it checks out I would spend some time with a die grinder and a dremel to clean up the bowls & guides.
I would also use self aligning rockers with them, when I put mine together with standard pushrod guide plates it made for a funky valve stem tip to rocker alignment. I then used adjustable guide plates, self aligning rockers would be a better option.